FIELD OF THE INVENTION
The invention relates generally to the field of multivalent binding molecules and therapeutic applications thereof.
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In a healthy mammal, the immune system protects the body from damage from foreign substances and pathogens. In some instances though, the immune system goes awry, producing traumatic insult and/or disease. For example, B-cells can produce antibodies that recognize self-proteins rather than foreign proteins, leading to the production of the autoantibodies characteristic of autoimmune diseases such as lupus erythematosus, rheumatoid arthritis, and the like. In other instances, the typically beneficial effect of the immune system in combating foreign materials is counterproductive, such as following organ transplantation. The power of the mammalian immune system, and in particular the human immune system, has been recognized and efforts have been made to control the system to avoid or ameliorate the deleterious consequences to health that result either from normal functioning of the immune system in an abnormal environment (e.g., organ transplantation) or from abnormal functioning of the immune system in an otherwise apparently normal environment (e.g., autoimmune disease progression). Additionally, efforts have been made to exploit the immune system to provide a number of target-specific diagnostic and therapeutic methodologies, relying on the capacity of antibodies to specifically recognize and bind antigenic targets with specificity.
One way in which the immune system protects the body is by production of specialized cells called B lymphocytes or B-cells. B-cells produce antibodies that bind to, and in some cases mediate destruction of, a foreign substance or pathogen. In some instances though, the human immune system, and specifically the B lymphocytes of the human immune system, go awry and disease results. There are numerous cancers that involve uncontrolled proliferation of B-cells. There are also numerous autoimmune diseases that involve B-cell production of antibodies that, instead of binding to foreign substances and pathogens, bind to parts of the body. In addition, there are numerous autoimmune and inflammatory diseases that involve B-cells in their pathology, for example, through inappropriate B-cell antigen presentation to T-cells or through other pathways involving B-cells. For example, autoimmune-prone mice deficient in B-cells do not develop autoimmune kidney disease, vasculitis or autoantibodies. (Shlomchik et al., J. Exp. Med. 1994, 180:1295-306). Interestingly, these same autoimmune-prone mice which possess B-cells but are deficient in immunoglobulin production, do develop autoimmune diseases when induced experimentally (Chan et al., J. Exp. Med. 1999, 189:1639-48), indicating that B-cells play an integral role in development of autoimmune disease.
B-cells can be identified by molecules on their cell surface. CD20 was the first human B-cell lineage-specific surface molecule identified by a monoclonal antibody. It is a non-glycosylated, hydrophobic 35 kDa B-cell transmembrane phosphoprotein that has both its amino and carboxy ends situated inside the cell. Einfeld et al., EMBO J. 1988, 7:711-17. CD20 is expressed by all normal mature B-cells, but is not expressed by precursor B-cells or plasma cells. Natural ligands for CD20 have not been identified, and the function of CD20 in B-cell biology is still incompletely understood.
Another B-cell lineage-specific cell surface molecule is CD37. CD37 is a heavily glycosylated 40-52 kDa protein that belongs to the tetraspanin transmembrane family of cell surface antigens. It traverses the cell membrane four times forming two extracellular loops and exposing its amino and carboxy ends to the cytoplasm. CD37 is highly expressed on normal antibody-producing (sIg+)B-cells, but is not expressed on pre-B-cells or plasma cells. The expression of CD37 on resting and activated T cells, monocytes and granulocytes is low and there is no detectable CD37 expression on NK cells, platelets or erythrocytes. See, Belov et al., Cancer Res., 61(11):4483-4489 (2001); Schwartz-Albiez et al., J. Immunol., 140(3): 905-914 (1988); and Link et al., J. Immunol., 137(9): 3013-3018 (1988). Besides normal B-cells, almost all malignancies of B-cell origin are positive for CD37 expression, including CLL, NHL, and hairy cell leukemia (Moore, et al. 1987; Merson and Brochier 1988; Faure, et al. 1990). CD37 participates in regulation of B-cell function, since mice lacking CD37 were found to have low levels of serum IgG1 and to be impaired in their humoral response to viral antigens and model antigens. It appears to act as a nonclassical costimulatory molecule or by directly influencing antigen presentation via complex formation with MHC class II molecules. See Knobeloch et al., Mol. Cell. Biol., 20(15):5363-5369 (2000).
Research and drug development has occurred based on the concept that B-cell lineage-specific cell surface molecules such as CD37 and CD20 can themselves be targets for antibodies that would bind to, and mediate destruction of, cancerous and autoimmune disease-causing B-cells that have CD37 and CD20 on their surfaces. Termed “immunotherapy,” antibodies made (or based on antibodies made) in a non-human animal that bind to CD37 or CD20 were given to a patient to deplete cancerous or autoimmune disease-causing B-cells.
Monoclonal antibody technology and genetic engineering methods have facilitated development of immunoglobulin molecules for diagnosis and treatment of human diseases. The domain structure of immunoglobulins is amenable to engineering, in that the antigen binding domains and the domains conferring effector functions may be exchanged between immunoglobulin classes and subclasses. Immunoglobulin structure and function are reviewed, for example, in Harlow et al., Eds., Antibodies: A Laboratory Manual, Chapter 14, Cold Spring Harbor Laboratory, Cold Spring Harbor (1988). An extensive introduction as well as detailed information about all aspects of recombinant antibody technology can be found in the textbook “Recombinant Antibodies” (John Wiley & Sons, NY, 1999). A comprehensive collection of detailed antibody engineering lab Protocols can be found in R. Kontermann and S. Dübel (eds.), “The Antibody Engineering Lab Manual” (Springer Verlag, Heidelberg/New York, 2000).
An immunoglobulin molecule (abbreviated Ig), is a multimeric protein, typically composed of two identical light chain polypeptides and two identical heavy chain polypeptides (H2L2) that are joined into a macromolecular complex by interchain disulfide bonds, i.e., covalent bonds between the sulfhydryl groups of neighboring cysteine residues. Five human immunoglobulin classes are defined on the basis of their heavy chain composition, and are named IgG, IgM, IgA, IgE, and IgD. The IgG-class and IgA-class antibodies are further divided into subclasses, namely, IgG1, IgG2, IgG3, and IgG4, and IgA1 and IgA2, respectively. Intrachain disulfide bonds join different areas of the same polypeptide chain, which results in the formation of loops that, along with adjacent amino acids, constitute the immunoglobulin domains. At the amino-terminal portion, each light chain and each heavy chain has a single variable region that shows considerable variation in amino acid composition from one antibody to another. The light chain variable region, VL, has a single antigen-binding domain and associates with the variable region of a heavy chain, VH (also containing a single antigen-binding domain), to form the antigen binding site of the immunoglobulin, the Fv.
In addition to variable regions, each of the full-length antibody chains has a constant region containing one or more domains. Light chains have a constant region containing a single domain. Thus, light chains have one variable domain and one constant domain. Heavy chains have a constant region containing several domains. The heavy chains in IgG, IgA, and IgD antibodies have three domains, which are designated CH1, CH2, and CH3; the heavy chains in IgM and IgE antibodies have four domains, CH1, CH2, CH3 and CH4. Thus, heavy chains have one variable domain and three or four constant domains. Noteworthy is the invariant organization of these domains in all known species, with the constant regions, containing one or more domains, being located at or near the C-terminus of both the light and heavy chains of immunoglobulin molecules, with the variable domains located towards the N-termini of the light and heavy chains. Immunoglobulin structure and function are reviewed, for example, in Harlow et al., Eds., Antibodies: A Laboratory Manual, Chapter 14, Cold Spring Harbor Laboratory, Cold Spring Harbor (1988).
The heavy chains of immunoglobulins can also be divided into three functional regions: the Fd region (a fragment comprising VH and CH1, i.e., the two N-terminal domains of the heavy chain), the hinge region, and the Fc region (the “fragment crystallizable” region). The Fc region contains the domains that interact with immunoglobulin receptors on cells and with the initial elements of the complement cascade. Thus, the Fc region or fragment is generally considered responsible for the effector functions of an immunoglobulin, such as ADCC (antibody-dependent cell-mediated cytotoxicity), CDC (complement-dependent cytotoxicity) and complement fixation, binding to Fc receptors, greater half-life in vivo relative to a polypeptide lacking an Fc region, protein A binding, and perhaps even placental transfer. Capon et al., Nature, 337: 525-531, (1989). Further, a polypeptide containing an Fc region allows for dimerization/multimerization of the polypeptide. These terms are also used for analogous regions of the other immunoglobulins.
Although all of the human immunoglobulin isotypes contain a recognizable structure in common, each isotype exhibits a distinct pattern of effector function. IgG, by way of nonexhaustive example, neutralizes toxins and viruses, opsonizes, fixes complement (CDC) and participates in ADCC. IgM, in contrast, neutralizes blood-borne pathogens and participates in opsonization. IgA, when associated with its secretory piece, is secreted and provides a primary defense to microbial infection via the mucosa; it also neutralizes toxins and supports opsonization. IgE mediates inflammatory responses, being centrally involved in the recruitment of other cells needed to mount a full response. IgD is known to provide an immunoregulatory function, controlling the activation of B cells. These characterizations of isotype effector functions provide a non-comprehensive illustration of the differences that can be found among human isotypes.
The hinge region, found in IgG, IgA, IgD, and IgE class antibodies, acts as a flexible spacer, allowing the Fab portion to move freely in space. In contrast to the constant regions, the hinge domains are structurally diverse, varying in both sequence and length among immunoglobulin classes and subclasses. For example, the length and flexibility of the hinge region varies among the IgG subclasses. The hinge region of IgG1 encompasses amino acids 216-231 and, because it is freely flexible, the Fab fragments can rotate about their axes of symmetry and move within a sphere centered at the first of two inter-heavy chain disulfide bridges. IgG2 has a shorter hinge than IgG1, with 12 amino acid residues and four disulfide bridges. The hinge region of IgG2 lacks a glycine residue, is relatively short, and contains a rigid poly-proline double helix, stabilized by extra inter-heavy chain disulfide bridges. These properties restrict the flexibility of the IgG2 molecule. IgG3 differs from the other subclasses by its unique extended hinge region (about four times as long as the IgG1 hinge), containing 62 amino acids (including 21 prolines and 11 cysteines), forming an inflexible poly-proline double helix. In IgG3, the Fab fragments are relatively far away from the Fc fragment, giving the molecule a greater flexibility. The elongated hinge in IgG3 is also responsible for its higher molecular weight compared to the other subclasses. The hinge region of IgG4 is shorter than that of IgG1 and its flexibility is intermediate between that of IgG1 and IgG2. The flexibility of the hinge regions reportedly decreases in the order IgG3>IgG1>IgG4>IgG2. The four IgG subclasses also differ from each other with respect to their effector functions. This difference is related to differences in structure, including differences with respect to the interaction between the variable region, Fab fragments, and the constant Fc fragment.
According to crystallographic studies, the immunoglobulin hinge region can be further subdivided functionally into three regions: the upper hinge region, the core region, and the lower hinge region. Shin et al., 1992 Immunological Reviews 130:87. The upper hinge region includes amino acids from the carboxyl end of CH1 to the first residue in the hinge that restricts motion, generally the first cysteine residue that forms an interchain disulfide bond between the two heavy chains. The length of the upper hinge region correlates with the segmental flexibility of the antibody. The core hinge region contains the inter-heavy chain disulfide bridges, and the lower hinge region joins the amino terminal end of the CH2 domain and includes residues in CH2. Id. The core hinge region of human IgG1 contains the sequence Cys-Pro-Pro-Cys which, when dimerized by disulfide bond formation, results in a cyclic octapeptide believed to act as a pivot, thus conferring flexibility. The hinge region may also contain one or more glycosylation sites, which include a number of structurally distinct types of sites for carbohydrate attachment. For example, IgA1 contains five glycosylation sites within a 17-amino-acid segment of the hinge region, conferring resistance of the hinge region polypeptide to intestinal proteases, considered an advantageous property for a secretory immunoglobulin.
Conformational changes permitted by the structure and flexibility of the immunoglobulin hinge region polypeptide sequence may also affect the effector functions of the Fc portion of the antibody. Three general categories of effector functions associated with the Fc region include (1) activation of the classical complement cascade, (2) interaction with effector cells, and (3) compartmentalization of immunoglobulins. The different human IgG subclasses vary in the relative efficacies with which they fix complement, or activate and amplify the steps of the complement cascade. See, e.g., Kirschfink, 2001 Immununol. Rev. 180:177; Chakraborti et al., 2000 Cell Signal 12:607; Kohl et al., 1999 Mol. Immunol. 36:893; Marsh et al., 1999 Curr. Opin. Nephrol. Hypertens. 8:557; Speth et al., 1999 Wien Klin. Wochenschr. 111:378.
Exceptions to the H2L2 structure of conventional antibodies occur in some isotypes of the immunoglobulins found in camelids (camels, dromedaries and llamas; Hamers-Casterman et al., 1993 Nature 363:446; Nguyen et al., 1998 J. Mol. Biol. 275:413), nurse sharks (Roux et al., 1998 Proc. Nat. Acad. Sci. USA 95:11804), and in the spotted ratfish (Nguyen, et al., 2002 Immunogenetics 54(1):39-47). These antibodies can apparently form antigen-binding regions using only heavy chain variable region, i.e., these functional antibodies are homodimers of heavy chains only (referred to as “heavy-chain antibodies” or “HCAbs”). Despite the advantages of antibody technology in disease diagnosis and treatment, there are some disadvantageous aspects of developing whole-antibody technologies as diagnostic and/or therapeutic reagents. Whole antibodies are large protein structures exemplified by the heterotetrameric structure of the IgG isotype, containing two light and two heavy chains. Such large molecules are sterically hindered in certain applications. For example, in treatments of solid tumors, whole antibodies do not readily penetrate the interior of the tumor. Moreover, the relatively large size of whole antibodies presents a challenge to ensure that the in vivo administration of such molecules does not induce an immune response. Further, generation of active antibody molecules typically involves the culturing of recombinant eukaryotic cells capable of providing appropriate post-translational processing of the nascent antibody molecules, and such cells can be difficult to culture and difficult to induce in a manner that provides commercially useful yields of active antibody.
Recently, smaller immunoglobulin molecules have been constructed to overcome problems associated with whole immunoglobulin methodologies. A single-chain variable antibody fragment (scFv) comprises an antibody heavy chain variable domain joined via a short peptide to an antibody light chain variable domain (Huston et al., Proc. Natl. Acad. Sci. USA, 1988, 85: 5879-83). Because of the small size of scFv molecules, they exhibit more effective penetration into tissues than whole immunoglobulin. An anti-tumor scFv showed more rapid tumor penetration and more even distribution through the tumor mass than the corresponding chimeric antibody (Yokota et al., Cancer Res. 1992, 52:3402-08).
Despite the advantages that scFv molecules bring to serotherapy, several drawbacks to this therapeutic approach exist. An scFv is rapidly cleared from the circulation, which may reduce toxic effects in normal cells, but such rapid clearance impedes delivery of a minimum effective dose to the target tissue. Manufacturing adequate amounts of scFv for administration to patients has been challenging due to difficulties in expression and isolation of scFv that adversely affect the yield. During expression, scFv molecules lack stability and often aggregate due to pairing of variable regions from different molecules. Furthermore, production levels of scFv molecules in mammalian expression systems are low, limiting the potential for efficient manufacturing of scFv molecules for therapy (Davis et al, J. Biol. Chem. 1990, 265:10410-18); Traunecker et al., EMBO J. 1991, 10: 3655-59). Strategies for improving production have been explored, including addition of glycosylation sites to the variable regions (Jost, C. R. U.S. Pat. No. 5,888,773, Jost et al, J. Biol. Chem. 1994, 69: 26267-73).
Another disadvantage to using scFv for therapy is the lack of effector function. An scFv without a cytolytic function, such as the antibody-dependent cell-mediated cytotoxicity (ADCC) and complement dependent-cytotoxicity (CDC) associated with the constant region of an immunoglobulin, may be ineffective for treating disease. Even though development of scFv technology began over 12 years ago, currently no scFv products are approved for therapy.
Alternatively, it has been proposed that fusion of an scFv to another molecule, such as a toxin, could take advantage of the specific antigen-binding activity and the small size of an scFv to deliver the toxin to a target tissue. Chaudary et al., Nature 1989, 339:394; Batra et al., Mol. Cell. Biol. 1991, 11:2200. Conjugation or fusion of toxins to scFvs has thus been offered as an alternative strategy to provide potent, antigen-specific molecules, but dosing with such conjugates or chimeras can be limited by excessive and/or non-specific toxicity due to the toxin moiety of such preparations. Toxic effects may include supraphysiological elevation of liver enzymes and vascular leak syndrome, and other undesired effects. In addition, immunotoxins are themselves highly immunogenic upon administration to a host, and host antibodies generated against the immunotoxin limit potential usefulness for repeated therapeutic treatments of an individual.
Nonsurgical cancer therapy, such as external irradiation and chemotherapy, can suffer from limited efficacy because of toxic effects on normal tissues and cells, due to the lack of specificity these treatments exhibit towards cancer cells. To overcome this limitation, targeted treatment methodologies have been developed to increase the specificity of the treatment for the cells and tissues in need thereof. An example of such a targeted methodology for in vivo use is the administration of antibody conjugates, with the antibody designed to specifically recognize a marker associated with a cell or tissue in need of treatment, and the antibody being conjugated to a therapeutic agent, such as a toxin in the case of cancer treatment. Antibodies, as systemic agents, circulate to sensitive and undesirable body compartments, such as the bone marrow. In acute radiation injury, destruction of lymphoid and hematopoietic compartments is a major factor in the development of septicemia and subsequent death. Moreover, antibodies are large, globular proteins that can exhibit poor penetration of tissues in need of treatment.
Human patients and non-human subjects suffering from a variety of end-stage disease processes frequently require organ transplantation. Organ transplantation, however, must contend with the untoward immune response of the recipient and guard against immunological rejection of the transplanted organ by depressing the recipient's cellular immune response to the foreign organ with cytotoxic agents which affect the lymphoid and other parts of the hematopoietic system. Graft acceptance is limited by the tolerance of the recipient to these cytotoxic chemicals, many of which are similar to the anticancer (antiproliferative) agents. Likewise, when using cytotoxic antimicrobial agents, particularly antiviral drugs, or when using cytotoxic drugs for autoimmune disease therapy, e.g., in treatment of systemic lupus erythematosis, a serious limitation is the toxic effects of the therapeutic agents on the bone marrow and the hematopoietic cells of the body.
Use of targeted therapies, such as targeted antibody conjugate therapy, is designed to localize a maximum quantity of the therapeutic agent at the site of desired action as possible, and the success of such therapies is revealed by the relatively high signal-to-background ratio of therapeutic agent. Examples of targeted antibodies include diagnostic or therapeutic agent conjugates of antibody or antibody fragments, cell- or tissue-specific peptides, and hormones and other receptor-binding molecules. For example, antibodies against different determinants associated with pathological and normal cells, as well as associated with pathogenic microorganisms, have been used for the detection and treatment of a wide variety of pathological conditions or lesions. In these methods, the targeting antibody is directly conjugated to an appropriate detecting or therapeutic agent as described, for example, in Hansen et al., U.S. Pat. No. 3,927,193 and Goldenberg, U.S. Pat. Nos. 4,331,647, 4,348,376, 4,361,544, 4,468,457, 4,444,744, 4,460,459, 4,460,561, 4,624,846 and 4,818,709.
One problem encountered in direct targeting methods, i.e., in methods wherein the diagnostic or therapeutic agent (the “active agent”) is conjugated directly to the targeting moiety, is that a relatively small fraction of the conjugate actually binds to the target site, while the majority of conjugate remains in circulation and compromises in one way or another the function of the targeted conjugate. To ensure maximal localization of the active agent, an excess of the targeted conjugate is typically administered, ensuring that some conjugate will remain unbound and contribute to background levels of the active agent. A diagnostic conjugate, e.g., a radioimmunoscintigraphic or magnetic resonance imaging conjugate that does not bind its target can remain in circulation, thereby increasing background and decreasing resolution of the diagnostic technique. In the case of a therapeutic conjugate having a toxin as an active agent (e.g., a radioisotope, drug or toxic compound) attached to a long-circulating targeting moiety such as an antibody, circulating conjugate can result in unacceptable toxicity to the host, such as marrow toxicity or systemic side effects.
U.S. Pat. No. 4,782,840 discloses a method for reducing the effect of elevated background radiation levels during surgery. The method involves injection of a patient with antibodies specific for neoplastic tissue, with the antibodies labeled with radioisotopes having a suitably long half-life, such as Iodine-125. After injection of the radiolabeled antibody, the surgery is delayed at least 7-10 days, preferably 14-21 days, to allow any unbound radiolabeled antibody to be cleared to a low background level.
U.S. Pat. No. 4,932,412 discloses methods for reducing or correcting for non-specific background radiation during intraoperative detection. The methods include the administration to a patient who has received a radiolabeled primary antibody, of a contrast agent, subtraction agent or second antibody which binds the primary antibody.
Apart from producing the antibodies described above, the immune system includes a variety of cell types that have powerful biological effects. During hematopoiesis, bone marrow-derived stem cells differentiate into either mature cells of the immune system (“B” cells) or into precursors of cells that migrate out of the bone marrow to mature in the thymus (“T” cells).
B cells are central to the humoral component of an immune response. B cells are activated by an appropriate presentation of an antigen to become antibody-secreting plasma cells; antigen presentation also results in clonal expansion of the activated B cell. B cells are primarily responsible for the humoral component of an immune response. A plasma cell typically exhibits about 105 antibody molecules (IgD and IgM) on its surface.
T lymphocytes can be divided into two categories. The cytotoxic T cells, Tc lymphocytes or CTLs (CD8+ T cells), kill cells bearing foreign surface antigen in association with Class I MHC and can kill cells that are harboring intracellular parasites (either bacteria or viruses) as long as the infected cell is displaying a microbial antigen on its surface. Tc cells kill tumor cells and account for the rejection of transplanted cells. Tc cells recognize antigen-Class I MHC complexes on target cells, contact them, and release the contents of granules directly into the target cell membrane, which lyses the cell.
A second category of T cells is the helper T cell or Th lymphocyte (CD4+ T cells), which produces lymphokines that are “helper” factors in the maturation of B cells into antibody-secreting plasma cells. Th cells also produce certain lymphokines that stimulate the differentiation of effector T lymphocytes and the activity of macrophages. Th1 cells recognize antigen on macrophages in association with Class II MHC and become activated (by IL-1) to produce lymphokines, including the IFN-γ that activates macrophages and NK cells. These cells mediate various aspects of the cell-mediated immunity response including delayed-type hypersensitivity reactions. Th2 cells recognize antigen in association with Class II MHC on an antigen presenting cell or APC (e.g., migratory macrophages and dendritic cells) and then produce interleukins and other substances that stimulate specific B-cell and T-cell proliferation and activity.
Beyond serving as APCs that initiate T cell interactions, development, and proliferation, macrophages are involved in expression of cell-mediated immunity because they become activated by IFN-γ produced in a cell-mediated immune response. Activated macrophages have increased phagocytic potential and release soluble substances that cause inflammation and destroy many bacteria and other cells. Natural Killer cells are cytotoxic cells that lyse cells bearing new antigen, regardless of their MHC type, and even lyse some cells that bear no MHC proteins. Natural Killer T cells, or NK cells, are defined by their ability to kill cells displaying a foreign antigen (e.g., tumor cells), regardless of MHC type, and regardless of previous sensitization (exposure) to the antigen. NK cells can be activated by IL-2 and IFN-γ, and lyse cells in the same manner as cytotoxic T lymphocytes. Some NK cells have receptors for the Fc domain of the IgG antibody (e.g, CD16 or FcγRIII) and are thus able to bind to the Fc portion of IgG on the surface of a target cell and release cytolytic components that kill the target cell via antibody-dependent cell-mediated cytotoxicity.
Another group of cells is the granulocytes or polymorphonuclear leukocytes (PMNs). Neutrophils, one type of PMN, kill bacterial invaders and phagocytose the remains. Eosinophils are another type of PMN and contain granules that prove cytotoxic when released upon another cell, such as a foreign cell. Basophils, a third type of PMN, are significant mediators of powerful physiological responses (e.g., inflammation) that exert their effects by releasing a variety of biologically active compounds, such as histamine, serotonin, prostaglandins, and leukotrienes. Common to all of these cell types is the capacity to exert a physiological effect within an organism, frequently by killing, and optionally scavenging, deleterious compositions such as foreign cells.
Although a variety of mammalian cells, including cells of the immune system, are capable of directly exerting a physiological effect (e.g., cell killing, typified by Tc, NK, some PMN, macrophage, and the like), other cells indirectly contribute to a physiological effect. For example, initial presentation of an antigen to a naïve T cell of the immune system requires MHC presentation that mandates cell-cell contact. Further, there often needs to be contact between an activated T cell and an antigen-specific B cell to obtain a particular immunogenic response. A third form of cell-cell contact often seen in immune responses is the contact between an activated B cell and follicular dendritic cells. Each of these cell-cell contact requirements complicates the targeting of a biologically active agent to a given target.
Complement-dependent cytotoxicity (CDC) is believed to be a significant mechanism for clearance of specific target cells such as tumor cells. CDC is a series of events that consists of a collection of enzymes that become activated by each other in a cascade fashion. Complement has an important role in clearing antigen, accomplished by its four major functions: (1) local vasodilation; (2) attraction of immune cells, especially phagocytes (chemotaxis); (3) tagging of foreign organisms for phagocytosis (opsonization); and (4) destruction of invading organisms by the membrane attack complex (MAC attack). The central molecule is the C3 protein. It is an enzyme that is split into two fragments by components of either the classical pathway or the alternative pathway. The classical pathway is induced by antibodies, especially IgG and IgM, while the alternative pathway is nonspecifically stimulated by bacterial products like lipopolysaccharide (LPS). Briefly, the products of the C3 split include a small peptide C3a which is chemotactic for phagocytic immune cells and results in local vasodilation by causing the release of C5a fragment from C5. The other part of C3, C3b, coats antigens on the surface of foreign organisms and acts to opsonize the organism for destruction. C3b also reacts with other components of the complement system to form an MAC consisting of C5b, C6, C7, C8 and C9.
There are problems associated with the use of antibodies in human therapy because the response of the immune system to any antigen, even the simplest, is “polyclonal,” i.e., the system manufactures antibodies of a great range of structures both in their binding regions as well as in their effector regions.
Two approaches have been used in an attempt to reduce the problem of immunogenic antibodies. The first is the production of chimeric antibodies in which the antigen-binding part (variable regions) of a mouse monoclonal antibody is fused to the effector part (constant region) of a human antibody. In a second approach, antibodies have been altered through a technique known as complementarity determining region (CDR) grafting or “humanization.” This process has been further improved to include changes referred to as “reshaping” (Verhoeyen, et al., 1988 Science 239:1534-1536; Riechmann, et al., 1988 Nature 332:323-337; Tempest, et al., Bio/Technol 1991 9:266-271), “hyperchimerization” (Queen, et al., 1989 Proc Natl Acad Sci USA 86:10029-10033; Co, et al., 1991 Proc Natl Acad Sci USA 88:2869-2873; Co, et al., 1992 J Immunol 148:1149-1154), and “veneering” (Mark, et al., In: Metcalf B W, Dalton B J, eds. Cellular adhesion: molecular definition to therapeutic potential. New York: Plenum Press, 1994:291-312).
An average of less than one therapeutic antibody per year has been introduced to the market beginning in 1986, eleven years after the publication of monoclonal antibodies. Five murine monoclonal antibodies were introduced into human medicine over a ten year period from 1986-1995, including “muromonab-CD3” (OrthoClone OKT3®) for acute rejection of organ transplants; “edrecolomab” (Panorex®) for colorectal cancer; “odulimomab” (Antilfa®) for transplant rejection; and, “ibritumomab” (Zevalin® yiuxetan) for non-Hodgkin's lymphoma. Additionally, a monoclonal Fab, “abciximab” (ReoPro®) has been marketed for preventing coronary artery reocclusion. Three chimeric monoclonal antibodies were also launched: “rituximab” (Rituxan®) for treating B cell lymphomas; “basiliximab” (Simulect®) for transplant rejection; and “infliximab” (Remicade®) for treatment of rheumatoid arthritis and Crohn's disease. Additionally, “abciximab” (ReoPro®), a 47.6 kD Fab fragment of a chimeric human-murine monoclonal antibody is marketed as an adjunct to percutaneous coronary intervention for the prevention of cardiac ischemic complications in patients undergoing percutaneous coronary intervention. Finally, seven “humanized” monoclonal antibodies have been launched. “Daclizumab” (Zenapax®) is used to prevent acute rejection of transplanted kidneys; “palivizumab” (Synagis®) for RSV; “trastuzumab” (Herceptin®) binds HER-2, a growth factor receptor found on breast cancers cells; “gemtuzumab” (Mylotarg®) for acute myelogenous leukemia (AML); and “alemtuzumab” (MabCampath®) for chronic lymphocytic leukemia; “adalimumab” (Humira® (D2E7)) for the treatment of rheumatoid arthritis; and, “omalizumab” (Xolair®), for the treatment of persistent asthma.
Thus, a variety of antibody technologies have received attention in the effort to develop and market more effective therapeutics and palliatives. Unfortunately, problems continue to compromise the promise of each of these therapies. For example, the majority of cancer patients treated with rituximab relapse, generally within about 6-12 months, and fatal infusion reactions within 24 hours of rituximab infusion have been reported. Acute renal failure requiring dialysis with instances of fatal outcome has also been reported in treatments with rituximab, as have severe, occasionally fatal, mucocutaneous reactions. Additionally, high doses of rituximab are required for intravenous injection because the molecule is large, approximately 150 kDa, and diffusion into the lymphoid tissues, where many tumor cells may reside is limited.
Trastuzumab administration can result in the development of ventricular dysfunction, congestive heart failure, and severe hypersensitivity reactions (including anaphylaxis), infusion reactions, and pulmonary events. Daclizumab immunosuppressive therapy poses an increased risk for developing lymphoproliferative disorders and opportunistic infections. Death from liver failure, arising from severe hepatotoxicity, and from veno-occlusive disease (VOD), has been reported in patients who received gemtuzumab.
Hepatotoxicity was also reported in patients receiving alemtuzumab. Serious and, in some rare instances fatal, pancytopenia/marrow hypoplasia, autoimmune idiopathic thrombocytopenia, and autoimmune hemolytic anemia have occurred in patients receiving alemtuzumab therapy. Alemtuzumab can also result in serious infusion reactions as well as opportunistic infections. In patients treated with adalimumab, serious infections and sepsis, including fatalities, have been reported, as has the exacerbation of clinical symptoms and/or radiographic evidence of demyelinating disease, and patients treated with adalimumab in clinical trials had a higher incidence of lymphoma than the expected rate in the general population. Omalizumab reportedly induces malignancies and anaphylaxis.
Cancer includes a broad range of diseases, affecting approximately one in four individuals worldwide. Rapid and unregulated proliferation of malignant cells is a hallmark of many types of cancer, including hematological malignancies. Although patients with a hematologic malignant condition have benefited from advances in cancer therapy in the past two decades, Multani et al., 1998 J. Clin. Oncology 16:3691-3710, and remission times have increased, most patients still relapse and succumb to their disease. Barriers to cure with cytotoxic drugs include, for example, tumor cell resistance and the high toxicity of chemotherapy, which prevents optimal dosing in many patients.
Treatment of patients with low grade or follicular B cell lymphoma using a chimeric CD20 monoclonal antibody has been reported to induce partial or complete responses in patients. McLaughlin et al., 1996 Blood 88:90a (abstract, suppl. 1); Maloney et al., 1997 Blood 90:2188-95. However, as noted above, tumor relapse commonly occurs within six months to one year. Further improvements in serotherapy are needed to induce more durable responses, for example, in low grade B cell lymphoma, and to allow effective treatment of high grade lymphoma and other B cell diseases.
Another approach has been to target radioisotopes to B cell lymphomas using monoclonal antibodies specific for CD20. While the effectiveness of therapy is reportedly increased, associated toxicity from the long in vivo half-life of the radioactive antibody increases, sometimes requiring that the patient undergo stem cell rescue. Press et al., 1993 N. Eng. J. Med. 329:1219-1224; Kaminski et al., 1993 N. Eng. J. Med. 329:459-65. Monoclonal antibodies to CD20 have also been cleaved with proteases to yield F(ab′)2 or Fab fragments prior to attachment of radioisotope. This has been reported to improve penetration of the radioisotope conjugate into the tumor and to shorten the in vivo half-life, thus reducing the toxicity to normal tissues. However, these molecules lack effector functions, including complement fixation and/or ADCC.
Autoimmune diseases include autoimmune thyroid diseases, which include Graves' disease and Hashimoto's thyroiditis. In the United States alone, there are about 20 million people who have some form of autoimmune thyroid disease. Autoimmune thyroid disease results from the production of autoantibodies that either stimulate the thyroid to cause hyperthyroidism (Graves' disease) or destroy the thyroid to cause hypothyroidism (Hashimoto's thyroiditis). Stimulation of the thyroid is caused by autoantibodies that bind and activate the thyroid stimulating hormone (TSH) receptor. Destruction of the thyroid is caused by autoantibodies that react with other thyroid antigens. Current therapy for Graves' disease includes surgery, radioactive iodine, or antithyroid drug therapy. Radioactive iodine is widely used, since antithyroid medications have significant side effects and disease recurrence is high. Surgery is reserved for patients with large goiters or where there is a need for very rapid normalization of thyroid function. There are no therapies that target the production of autoantibodies responsible for stimulating the TSH receptor. Current therapy for Hashimoto's thyroiditis is levothyroxine sodium, and lifetime therapy is expected because of the low likelihood of remission. Suppressive therapy has been shown to shrink goiters in Hashimoto's thyroiditis, but no therapies that reduce autoantibody production to target the disease mechanism are known.
Rheumatoid arthritis (RA) is a chronic disease characterized by inflammation of the joints, leading to swelling, pain, and loss of function. RA affects an estimated 2.5 million people in the United States. RA is caused by a combination of events including an initial infection or injury, an abnormal immune response, and genetic factors. While autoreactive T cells and B cells are present in RA, the detection of high levels of antibodies that collect in the joints, called rheumatoid factor, is used in the diagnosis of RA. Current therapy for RA includes many medications for managing pain and slowing the progression of the disease. No therapy has been found that can cure the disease. Medications include nonsteroidal anti-inflammatory drugs (NSAIDS), and disease modifying anti-rheumatic drugs (DMARDS). NSAIDS are useful in benign disease, but fail to prevent the progression to joint destruction and debility in severe RA. Both NSAIDS and DMARDS are associated with significant side effects. Only one new DMARD, Leflunomide, has been approved in over 10 years. Leflunomide blocks production of autoantibodies, reduces inflammation, and slows progression of RA. However, this drug also causes severe side effects including nausea, diarrhea, hair loss, rash, and liver injury.
Systemic Lupus Erythematosus (SLE) is an autoimmune disease caused by recurrent injuries to blood vessels in multiple organs, including the kidney, skin, and joints. SLE is estimated to affect over 500,000 people in the United States. In patients with SLE, a faulty interaction between T cells and B cells results in the production of autoantibodies that attack the cell nucleus. These include anti-double stranded DNA and anti-Sm antibodies. Autoantibodies that bind phospholipids are also found in about half of SLE patients, and are responsible for blood vessel damage and low blood counts. Immune complexes accumulate in the kidneys, blood vessels, and joints of SLE patients, where they cause inflammation and tissue damage. No treatment for SLE has been found to cure the disease. NSAIDS and DMARDS are used for therapy depending upon the severity of the disease. Plasmapheresis with plasma exchange to remove autoantibodies can cause temporary improvement in SLE patients. There is general agreement that autoantibodies are responsible for SLE, so new therapies that deplete the B cell lineage, allowing the immune system to reset as new B cells are generated from precursors, would offer hope for long lasting benefit in SLE patients.
Sjogren's syndrome is an autoimmune disease characterized by destruction of the body's moisture-producing glands. Sjogren's syndrome is one of the most prevalent autoimmune disorders, striking up to an estimated 4 million people in the United States. About half of the people stricken with Sjogren's syndrome also have a connective tissue disease, such as RA, while the other half have primary Sjogren's syndrome with no other concurrent autoimmune disease. Autoantibodies, including anti-nuclear antibodies, rheumatoid factor, anti-fodrin, and anti-muscarinic receptor are often present in patients with Sjogren's syndrome. Conventional therapy includes corticosteroids, and additional more effective therapies would be of benefit.
Immune thrombocytopenic purpura (ITP) is caused by autoantibodies that bind to blood platelets and cause their destruction. Some cases of ITP are caused by drugs, and others are associated with infection, pregnancy, or autoimmune disease such as SLE. About half of all cases are classified as being of idiopathic origin. The treatment of ITP is determined by the severity of the symptoms. In some cases, no therapy is needed although in most cases immunosuppressive drugs, including corticosteroids or intravenous infusions of immune globulin to deplete T cells, are provided. Another treatment that usually results in an increased number of platelets is removal of the spleen, the organ that destroys antibody-coated platelets. More potent immunosuppressive drugs, including cyclosporine, cyclophosphamide, or azathioprine are used for patients with severe cases. Removal of autoantibodies by passage of patients' plasma over a Protein A column is used as a second line treatment in patients with severe disease. Additional more effective therapies are needed.
Multiple sclerosis (MS) is also an autoimmune disease. It is characterized by inflammation of the central nervous system and destruction of myelin, which insulates nerve cell fibers in the brain, spinal cord, and body. Although the cause of MS is unknown, it is widely believed that autoimmune T cells are primary contributors to the pathogenesis of the disease. However, high levels of antibodies are present in the cerebrospinal fluid of patients with MS, and some predict that the B cell response leading to antibody production is important for mediating the disease. No B cell depletion therapies have been studied in patients with MS, and there is no cure for MS. Current therapy is corticosteroids, which can reduce the duration and severity of attacks, but do not affect the course of MS over time. New biotechnology interferon (IFN) therapies for MS have recently been approved but additional more effective therapies are required.
Myasthenia Gravis (MG) is a chronic autoimmune neuromuscular disorder that is characterized by weakness of the voluntary muscle groups. MG affects about 40,000 people in the United States. MG is caused by autoantibodies that bind to acetylcholine receptors expressed at neuromuscular junctions. The autoantibodies reduce or block acetylcholine receptors, preventing the transmission of signals from nerves to muscles. There is no known cure for mg. Common treatments include immunosuppression with corticosteroids, cyclosporine, cyclophosphamide, or azathioprine. Surgical removal of the thymus is often used to blunt the autoimmune response. Plasmapheresis, used to reduce autoantibody levels in the blood, is effective in mg, but is short-lived because the production of autoantibodies continues. Plasmapheresis is usually reserved for severe muscle weakness prior to surgery. New and effective therapies would be of benefit.
Psoriasis affects approximately five million people, and is characterized by autoimmune inflammation in the skin. Psoriasis is also associated with arthritis in 30% (psoriatic arthritis). Many treatments, including steroids, uv light retinoids, vitamin D derivatives, cyclosporine, and methotrexate have been used but it is also clear that psoriasis would benefit from new and effective therapies. Scleroderma is a chronic autoimmune disease of the connective tissue that is also known as systemic sclerosis. Scleroderma is characterized by an overproduction of collagen, resulting in a thickening of the skin, and approximately 300,000 people in the United States have scleroderma, which would also benefit from new and effective therapies.
Apparent from the foregoing discussion are needs for improved compositions and methods to treat, ameliorate or prevent a variety of diseases, disorders and conditions, including cancer and autoimmune diseases.
The invention satisfies at least one of the aforementioned needs in the art by providing proteins containing at least two specific binding domains, wherein those two domains are linked by a constant sub-region derived from an antibody molecule attached at its C-terminus to a linker herein referred to as a scorpion linker, and nucleic acids encoding such proteins, as well as production, diagnostic and therapeutic uses of such proteins and nucleic acids. The constant sub-region comprises a domain derived from an immunoglobulin CH2 domain, and preferably a domain derived from an immunoglobulin CH3 domain, but does not contain a domain or region derived from, or corresponding to, an immunoglobulin CH1 domain. Previously, it had been thought that the placement of a constant region derived from an antibody in the interior of a protein would interfere with antibody function, such as effector function, by analogy to the conventional placement of constant regions of antibodies at the carboxy termini of antibody chains. In addition, placement of a scorpion linker, which may be an immunoglobulin hinge-like peptide, C-terminal to a constant sub-region is an organization that differs from the organization of naturally occurring immunoglobulins. Placement of a constant sub-region (with a scorpion linker attached C-terminal to the constant region) in the interior of a polypeptide or protein chain in accordance with the invention, however, resulted in proteins exhibiting effector function and multivalent (mono- or multi-specific) binding capacities relatively unencumbered by steric hindrances. As will be apparent to one of skill in the art upon consideration of this disclosure, such proteins are modular in design and may be constructed by selecting any of a variety of binding domains for binding domain 1 or binding domain 2 (or for any additional binding domains found in a particular protein according to the invention), by selecting a constant sub-region having effector function, and by selecting a scorpion linker, hinge-like or non-hinge like (e.g., type II C-lectin receptor stalk region peptides), with the protein exhibiting a general organization of N-binding domain 1-constant sub-region-scorpion linker-binding domain 2-C. Those of skill will further appreciate that proteins of such structure, and the nucleic acids encoding those proteins, will find a wide variety of applications, including medical and veterinary applications.
One aspect of the invention is drawn to a multivalent single-chain binding protein with effector function, or scorpion (the terms are used interchangeably), comprising a first binding domain derived from an immunoglobulin (e.g., an antibody) or an immunoglobulin-like molecule, a constant sub-region providing an effector function, the constant sub-region located C-terminal to the first binding domain; a scorpion linker located C-terminal to the constant sub-region; and a second binding domain derived from an immunoglobulin (such as an antibody) or immunoglobulin-like molecule, located C-terminal to the constant sub-region; thereby localizing the constant sub-region between the first binding domain and the second binding domain. The single-chain binding protein may be multispecific, e.g., bispecific in that it could bind two or more distinct targets, or it may be monospecific, with two binding sites for the same target. Moreover, all of the domains of the protein are found in a single chain, but the protein may form homo-multimers, e.g., by interchain disulfide bond formation. In some embodiments, the first binding domain and/or the second binding domain is/are derived from variable regions of light and heavy immunoglobulin chains from the same, or different, immunoglobulins (e.g., antibodies). The immunoglobulin(s) may be from any vertebrate, such as a mammal, including a human, and may be chimeric, humanized, fragments, variants or derivatives of naturally occurring immunoglobulins.
The invention contemplates proteins in which the first and second binding domains are derived from the same, or different immunoglobulins (e.g., antibodies), and wherein the first and second binding domains recognize the same, or different, molecular targets (e.g., cell surface markers, such as membrane-bound proteins). Further, the first and second binding domains may recognize the same, or different, epitopes. The first and second molecular targets may be associated with first and second target cells, viruses, carriers and/or objects. In preferred embodiments according to this aspect of the invention, each of the first binding domain, second binding domain, and constant sub-region is derived from a human immunoglobulin, such as an IgG antibody. In yet other embodiments, the multivalent binding protein with effector function has at least one of the first binding domain and the second binding domain that recognizes at least one cell-free molecular target, e.g., a protein unassociated with a cell, such as a deposited protein or a soluble protein. Cell-free molecular targets include, e.g., proteins that were never associated with a cell, e.g., administered compounds such as proteins, as well as proteins that are secreted, cleaved, present in exosomes, or otherwise discharged or separated from a cell.
The target molecules recognized by the first and second binding domains may be found on, or in association with, the same, or different, prokaryotic cells, eukaryotic cells, viruses (including bacteriophage), organic or inorganic target molecule carriers, and foreign objects. Moreover, those target molecules may be on physically distinct cells, viruses, carriers or objects of the same type (e.g., two distinct eukaryotic cells, prokaryotic cells, viruses or carriers) or those target molecules may be on cells, viruses, carriers, or objects that differ in type (e.g., a eukaryotic cell and a virus). Target cells are those cells associated with a target molecule recognized by a binding domain and includes endogenous or autologous cells as well as exogenous or foreign cells (e.g., infectious microbial cells, transplanted mammalian cells including transfused blood cells). The invention comprehends targets for the first and/or second binding domains that are found on the surface of a target cell(s) associated with a disease, disorder or condition of a mammal such as a human. Exemplary target cells include a cancer cell, a cell associated with an autoimmune disease or disorder, and an infectious cell (e.g., an infectious bacterium). A cell of an infectious organism, such as a mammalian parasite, is also contemplated as a target cell. In some embodiments, a protein of the invention is a multivalent (e.g., multispecific) binding protein with effector function wherein at least one of the first binding domain and the second binding domain recognizes a target selected from the group consisting of a tumor antigen, a B-cell target, a TNF receptor superfamily member, a Hedgehog family member, a receptor tyrosine kinase, a proteoglycan-related molecule, a TGF-beta superfamily member, a Wnt-related molecule, a receptor ligand, a T-cell target, a Dendritic cell target, an NK cell target, a monocyte/macrophage cell target and an angiogenesis target.
In some embodiments of the above-described protein, the tumor antigen is selected from the group consisting of SQUAMOUS CELL CARCINOMA ANTIGEN 1 (SCCA-1), (PROTEIN T4-A), SQUAMOUS CELL CARCINOMA ANTIGEN 2 (SCCA-2), Ovarian carcinoma antigen CA125 (1A1-3B) (KIAA0049), MUCIN 1 (TUMOR-ASSOCIATED MUCIN), (CARCINOMA-ASSOCIATED MUCIN), (POLYMORPHIC EPITHELIAL MUCIN), (PEM), (PEMT), (EPISIALIN), (TUMOR-ASSOCIATED EPITHELIAL MEMBRANE ANTIGEN), (EMA), (H23AG), (PEANUT-REACTIVE URINARY MUCIN), (PUM), (BREAST CARCINOMA-ASSOCIATED ANTIGEN DF3), CTCL tumor antigen se1-1, CTCL tumor antigen se14-3, CTCL tumor antigen se20-4, CTCL tumor antigen se20-9, CTCL tumor antigen se33-1, CTCL tumor antigen se37-2, CTCL tumor antigen se57-1, CTCL tumor antigen se89-1, Prostate-specific membrane antigen, 5T4 oncofetal trophoblast glycoprotein, Orf73 Kaposi\'s sarcoma-associated herpesvirus, MAGE-C1 (cancer/testis antigen CT7), MAGE-B1 ANTIGEN (MAGE-XP ANTIGEN) (DAM10), MAGE-B2 ANTIGEN (DAM6), MAGE-2 ANTIGEN, MAGE-4-a antigen, MAGE-4-b antigen, Colon cancer antigen NY-CO-45, Lung cancer antigen NY-LU-12 variant A, Cancer associated surface antigen, Adenocarcinoma antigen ART1, Paraneoplastic associated brain-testis-cancer antigen (onconeuronal antigen MA2; paraneoplastic neuronal antigen), Neuro-oncological ventral antigen 2 (NOVA2), Hepatocellular carcinoma antigen gene 520, TUMOR-ASSOCIATED ANTIGEN CO-029, Tumor-associated antigen MAGE-X2, Synovial sarcoma, X breakpoint 2, Squamous cell carcinoma antigen recognized by T cell, Serologically defined colon cancer antigen 1, Serologically defined breast cancer antigen NY-BR-15, Serologically defined breast cancer antigen NY-BR-16, Chromogranin A; parathyroid secretory protein 1, DUPAN-2, CA 19-9, CA 72-4, CA 195 and L6.
Embodiments of the above-described method comprise a B cell target selected from the group consisting of CD10, CD19, CD20, CD21, CD22, CD23, CD24, CD37, CD38, CD39, CD40, CD72, CD73, CD74, CDw75, CDw76, CD77, CD78, CD79a/b, CD80, CD81, CD82, CD83, CD84, CD85, CD86, CD89, CD98, CD126, CD127, CDw130, CD138 and CDw150.
In other embodiments of the above-described method, the TNF receptor superfamily member is selected from the group consisting of 4-1BB/TNFRSF9, NGF R/TNFRSF16, BAFF R/TNFRSF13C, Osteoprotegerin/TNFRSF11B, BCMA/TNFRSF17, OX40/TNFRSF4, CD27/TNFRSF7, RANK/TNFRSF11A, CD30/TNFRSF8, RELT/TNFRSF19L, CD40/TNFRSF5, TACl/TNFRSF13B, DcR3/TNFRSF6B, TNF RI/TNFRSF1A, DcTRAIL R1/TNFRSF23, TNF RII/TNFRSF1B, DcTRAIL R2/TNFRSF22, TRAIL R1/TNFRSF10A, DR3/TNFRSF25, TRAIL R2/TNFRSF10B, DR6/TNFRSF21, TRAIL R3/TNFRSF10C, EDAR, TRAIL R4/TNFRSF10D, Fas/TNFRSF6, TROY/TNFRSF19, GITR/TNFRSF18, TWEAK R/TNFRSF12, HVEM/TNFRSF14, XEDAR, Lymphotoxin beta R/TNFRSF3, 4-1BB Ligand/TNFSF9, Lymphotoxin, APRIL/TNFSF13, Lymphotoxin beta/TNFSF3, BAFF/TNFSF13C, OX40 Ligand/TNFSF4, CD27 Ligand/TNFSF7, TL1A/TNFSF15, CD30 Ligand/TNFSF8, TNF-alpha/TNFSF1A, CD40 Ligand/TNFSF5, TNF-beta/TNFSF1B, EDA-A2, TRAIL/TNFSF10, Fas Ligand/TNFSF6, TRANCE/TNFSF11, GITR Ligand/TNFSF18, TWEAK/TNFSF12 and LIGHT/TNFSF14.
The above-described method also includes embodiments in which the Hedgehog family member is selected from the group consisting of Patched and Smoothened. In yet other embodiments, the proteoglycan-related molecule is selected from the group consisting of proteoglycans and regulators thereof.
Additional embodiments of the method are drawn to processes in which the receptor tyrosine kinase is selected from the group consisting of Ax1, FGF R4, C1q R1/CD93, FGF R5, DDR1, Flt-3, DDR2, HGF R, Dtk, IGF-I R, EGF R, IGF-II R, Eph, INSRR, EphA1, Insulin R/CD220, EphA2, M-CSF R, EphA3, Mer, EphA4, MSP R/Ron, EphA5, MuSK, EphA6, PDGF R alpha, EphA7, PDGF R beta, EphA8, Ret, EphBl, ROR1, EphB2, ROR2, EphB3, SCF R/c-kit, EphB4, Tie-1, EphB6, Tie-2, ErbB2, TrkA, ErbB3, TrkB, ErbB4, TrkC, FGF R1, VEGF FGF R2, VEGF R2/Flk-1, FGF R3 and VEGF R3/Flt-4.
In other embodiments of the method, the Transforming Growth Factor (TGF)-beta superfamily member is selected from the group consisting of Activin RIA/ALK-2, GFR alpha-1, Activin RIB/ALK-4, GFR alpha-2, Activin RIIA, GFR alpha-3, Activin RIIB, GFR alpha-4, ALK-1, MIS RII, ALK-7, Ret, BMPR-IA/ALK-3, TGF-beta RI/ALK-5, BMPR-IB/ALK-6, TGF-beta RII, BMPR-II, TGF-beta RIIb, Endoglin/CD 105 and TGF-beta RIII.
Yet other embodiments of the method comprise a Wnt-related molecule selected from the group consisting of Frizzled-1, Frizzled-8, Frizzled-2, Frizzled-9, Frizzled-3, sFRP-1, Frizzled-4, sFRP-2, Frizzled-5, sFRP-3, Frizzled-6, sFRP-4, Frizzled-7, MFRP, LRP 5, LRP 6, Wnt-1, Wnt-8a, Wnt-3a, Wnt-10b, Wnt-4, Wnt-11, Wnt-5a, Wnt-9a and Wnt-7a.
In other embodiments of the method, the receptor ligand is selected from the group consisting of 4-1BB Ligand/TNFSF9, Lymphotoxin, APRIL/TNFSF13, Lymphotoxin beta/TNFSF3, BAFF/TNFSF13C, OX40 Ligand/TNFSF4, CD27 Ligand/TNFSF7, TLIA/TNFSF15, CD30 Ligand/TNFSF8, TNF-alpha/TNFSF1A, CD40 Ligand/TNFSF5, TNF-beta/TNFSF1B, EDA-A2, TRAIL/TNFSF10, Fas Ligand/TNFSF6, TRANCE/TNFSF11, GITR Ligand/TNFSF18, TWEAK/TNFSF12, LIGHT/TNFSF14, Amphiregulin, NRG1 isoform GGF2, Betacellulin, NRG1 Isoform SMDF, EGF, NRG1-alpha/HRG1-alpha, Epigen, NRG1-beta 1/HRG1-beta 1, Epiregulin, TGF-alpha, HB-EGF, TMEFF1/Tomoregulin-1, Neuregulin-3, TMEFF2, IGF-I, IGF-II, Insulin, Activin A, Activin B, Activin AB, Activin C, BMP-2, BMP-7, BMP-3, BMP-8, BMP-3b/GDF-10, BMP-9, BMP-4, BMP-15, BMP-5, Decapentaplegic, BMP-6, GDF-1, GDF-8, GDF-3, GDF-9, GDF-5, GDF-11, GDF-6, GDF-15, GDF-7, Artemin, Ncurturin, GDNF, Persephin, TGF-beta, TGF-beta 2, TGF-beta 1, TGF-beta 3, LAP (TGF-beta 1), TGF-beta 5, Latent TGF-beta 1, Latent TGF-beta bpl, TGF-beta 1.2, Lefty, Nodal, MIS/AMH, FGF acidic, FGF-12, FGF basic, FGF-13, FGF-3, FGF-16, FGF-4, FGF-17, FGF-5, FGF-19, FGF-6, FGF-20, FGF-8, FGF-21, FGF-9, FGF-23, FGF-10, KGF/FGF-7, FGF-11, Neuropilin-1, P1GF, Neuropilin-2, P1GF-2, PDGF, PDGF-A, VEGF, PDGF-B, VEGF-B, PDGF-C, VEGF-C, PDGF-D, VEGF-D and PDGF-AB.
In still other embodiments, the T-cell target is selected from the group consisting of 2B4/SLAMF4, IL-2 R alpha, 4-1BB/TNFRSF9, IL-2 R beta, ALCAM, B7-1/CD80, IL-4 R, B7-H3, BLAME/SLAMF8, BTLA, IL-6 R, CCR3, IL-7 R alpha, CCR4, CXCRI/IL-8 RA, CCR5, CCR6, IL-10 R alpha, CCR7, IL-10 R beta, CCR8, IL-12 R beta 1, CCR9, IL-12 R beta 2, CD2, IL-13 R alpha 1, IL-13, CD3, CD4, ILT2/CD85j, ILT3/CD85k, ILT4/CD85d, ILT5/CD85a, Integrin alpha 4/CD49d, CD5, Integrin alpha E/CD103, CD6, Integrin alpha M/CD11b, CD8, Integrin alpha X/CD11c, Integrin beta 2/CD18, KIR/CD158, CD27/TNFRSF7, KIR2DL1, CD28, KIR2DL3, CD30/TNFRSF8, KIR2DL4/CD158d, CD31/PECAM-1, KIR2DS4, CD40 Ligand/TNFSF5, LAG-3, CD43, LAIR1, CD45, LAIR2, CD83, Leukotriene B4 R1, CD84/SLAMF5, NCAM-L1, CD94, NKG2A, CD97, NKG2C, CD229/SLAMF3, NKG2D, CD2F-10/SLAMF9, NT-4, CD69, NTB-A/SLAMF6, Common gamma Chain/IL-2 R gamma, Osteopontin, CRACC/SLAMF7, PD-1, CRTAM, PSGL-1, CTLA-4, RANK/TNFRSF111A, CX3CR1, CX3CL1, L-Selectin, CXCR3, SIRP beta 1, CXCR4, SLAM, CXCR6, TCCR/WSX-1, DNAM-1, Thymopoietin, EMMPRIN/CD147, TIM-1, EphB6, TIM-2, Fas/TNFRSF6, TIM-3, Fas Ligand/TNFSF6, TIM-4, Fc gamma RIII/CD16, TIM-6, GITR/INFRSF18, TNF RI/TNFRSF1A, Granulysin, TNF RII/TNFRSF1B, HVEM/TNFRSF14, TRAIL R1/TNFRSF10A, ICAM-1/CD54, TRAIL R2/TNFRSF10B, ICAM-2/CD102, TRAIL R3/TNFRSF10C, IFN-gamma R1, TRAIL R4/TNFRSF10D, IFN-gamma R2, TSLP, IL-1 RI and TSLP R.
In other embodiments, the NK cell receptor is selected from the group consisting of 2B4/SLAMF4, KIR2DS4, CD155/PVR, KIR3DL1, CD94, LMIRI/CD300A, CD69, LMIR2/CD300c, CRACC/SLAMF7, LMIR3/CD300LF, DNAM-1, LMIR5/CD300LB, Fc epsilon RII, LMIR6/CD300LE, Fc gamma R1/CD64, MICA, Fc gamma RIIB/CD32b, MICB, Fc gamma RIIC/CD32c, MULT-1, Fc gamma RIIA/CD32a, Nectin-2/CD112, Fc gamma RIII/CD16, NKG2A, FcRH1/IRTA5, NKG2C, FcRH2/IRTA4, NKG2D, FcRH4/IRTA1, NKp30, FcRH5/IRTA2, NKp44, Fc Receptor-like 3/CD16-2, NKp46/NCR1, NKp80/KLRF1, NTB-A/SLAMF6, Rae-1, Rae-1 alpha, Rae-1 beta, Rae-1 delta, H60, Rae-1 epsilon, 1LT2/CD85j, Rae-1 gamma, ILT3/CD85k, TREM-1, ILT4/CD85d, TREM-2, ILT5/CD85a, TREM-3, KIR/CD158, TREML1/TLT-1, KIR2DL1, ULBP-1, KIR2DL3, ULBP-2, KIR2DL4/CD158d and ULBP-3.
In other embodiments, the monocyte/macrophage cell target is selected from the group consisting of B7-1/CD80, ILT4/CD85d, B7-H1, ILT5/CD85a, Common beta Chain, Integrin alpha 4/CD49d, BLAME/SLAMF8, Integrin alpha X/CD11c, CCL6/C10, Integrin beta 2/CD18, CD155/PVR, Integrin beta 3/CD61, CD31/PECAM-1, Latexin, CD36/SR-B3, Leukotriene B4 R1, CD40/TNFRSF5, LIMPII/SR-B2, CD43, LMIRI/CD300A, CD45, LMIR2/CD300c, CD68, LMIR3/CD300LF, CD84/SLAMF5, LMIR5/CD300LB, CD97, LMIR6/CD300LE, CD163, LRP-1, CD2F-10/SLAMF9, MARCO, CRACC/SLAMF7, MD-1, ECF-L, MD-2, EMMPRIN/CD 147, MGL2, Endoglin/CD 105, Osteoactivin/GPNMB, Fc gamma RI/CD64, Osteopontin, Fc gamma RIIB/CD32b, PD-L2, Fc gamma RIIC/CD32c, Siglec-3/CD33, Fc gamma RIIA/CD32a, SIGNR1/CD209, Fc gamma RIII/CD16, SLAM, GM-CSF R alpha, TCCR/WSX-1, ICAM-2/CD102, TLR3, IFN-gamma R1, TLR4, IFN-gamma R2, TREM-1, IL-1 RII, TREM-2, ILT2/CD85j, TREM-3, ILT3/CD85k, TREML1/TLT-1, 2B4/SLAMF4, IL-10 R alpha, ALCAM, IL-10 R beta, Aminopeptidase N/ANPEP, ILT2/CD85j, Common beta Chain, ILT3/CD85k, C1q R1/CD93, ILT4/CD85d, CCR1, ILT5/CD85a, CCR2, Integrin alpha 4/CD49d, CCR5, Integrin alpha M/CD11b, CCR8, Integrin alpha X/CD11c, CD155/PVR, Integrin beta 2/CD18, CD14, Integrin beta 3/CD61, CD36/SR-B3, LAIR1, CD43, LAIR2, CD45, Leukotriene B4 R1, CD68, LIMPII/SR-B2, CD84/SLAMF5, LMIR1/CD300A, CD97, LMIR2/CD300c, CD163, LMIR3/CD300LF, Coagulation Factor III/Tissue Factor, LMIR5/CD300LB, CX3CR1, CX3CL1, LMIR6/CD300LE, CXCR4, LRP-1, CXCR6, M-CSF R, DEP-1/CD148, MD-1, DNAM-1, MD-2, EMMPRIN/CD147, MMR, Endoglin/CD105, NCAM-L1, Fc gamma RI/CD64, PSGL-1, Fc gamma RIII/CD16, RP105, G-CSF R, L-Selectin, GM-CSF R alpha, Siglec-3/CD33, HVEM/TNFRSF14, SLAM, ICAM-1/CD54, TCCR/WSX-1, ICAM-2/CD102, TREM-1, IL-6 R, TREM-2, CXCR1/IL-8 RA, TREM-3 and TREML1/TLT-1.
In yet other embodiments of the method, a Dendritic cell target is selected from the group consisting of CD36/SR-B3, LOX-1/SR-E1, CD68, MARCO, CD163, SR-AI/MSR, CD5L, SREC-I, CL-P1/COLEC12, SREC-II, LIMPII/SR-B2, RP105, TLR4, TLR1, TLR5, TLR2, TLR6, TLR3, TLR9, 4-1BB Ligand/TNFSF9, IL-12/IL-23 p40, 4-Amino-1,8-naphthalimide, ILT2/CD85j, CCL21/6Ckine, ILT3/CD85k, 8-oxo-dG, ILT4/CD85d, 8D6A, ILT5/CD85a, A2B5, Integrin alpha 4/CD49d, Aag, Integrin beta 2/CD18, AMICA, Langerin, B7-2/CD86, Leukotriene B4 R1, B7-H3, LMIRI/CD300A, BLAME/SLAMF8, LMIR2/CD300c, C1q R1/CD93, LMIR3/CD300LF, CCR6, LMIR5/CD300LB, CCR7, LMIR6/CD300LE, CD40/TNFRSF5, MAG/Siglec-4-a, CD43, MCAM, CD45, MD-1, CD68, MD-2, CD83, MDL-1/CLEC5A, CD84/SLAMF5, MMR, CD97, NCAM-L1, CD2F-10/SLAMF9, Ostcoactivin/GPNMB, Chem 23, PD-L2, CLEC-1, RP105, CLEC-2, Siglec-2/CD22, CRACC/SLAMF7, Siglec-3/CD33, DC-SIGN, Siglec-5, DC-SIGNR/CD299, Siglec-6, DCAR, Siglec-7, DCIR/CLEC4A, Siglec-9, DEC-205, Siglec-10, Dectin-1/CLEC7A, Siglec-F, Dectin-2/CLEC6A, SIGNR1/CD209, DEP-1/CD148, SIGNR4, DLEC, SLAM, EMMPRIN/CD147, TCCR/WSX-1, Fc gamma RI/CD64, TLR3, Fc gamma RIIB/CD32b, TREM-1, Fc gamma RIIC/CD32c, TREM-2, Fc gamma RIIA/CD32a, TREM-3, Fc gamma RIII/CD16, TREML1/TLT-1, ICAM-2/CD102 and Vanilloid R1.
In still other embodiments of the method, the angiogenesis target is selected from the group consisting of Angiopoietin-1, Angiopoietin-like 2, Angiopoietin-2, Angiopoietin-like 3, Angiopoietin-3, Angiopoietin-like 7/CDT6, Angiopoietin-4, Tie-1, Angiopoietin-like 1, Tie-2, Angiogenin, iNOS, Coagulation Factor III/Tissue Factor, nNOS, CTGF/CCN2, NOV/CCN3, DANCE, OSM, EDG-1, Plfr, EG-VEGF/PK1, Proliferin, Endostatin, ROBO4, Erythropoietin, Thrombospondin-1, Kininostatin, Thrombospondin-2, MFG-E8, Thrombospondin-4, Nitric Oxide, VG5Q, eNOS, EphA1, EphA5, EphA2, EphA6, EphA3, EphA7, EphA4, EphA8, EphB1, EphB4, EphB2, EphB6, EphB3, Ephrin-A1, Ephrin-A4, Ephrin-A2, Ephrin-A5, Ephrin-A3, Ephrin-B1, Ephrin-B3, Ephrin-B2, FGF acidic, FGF-12, FGF basic, FGF-13, FGF-3, FGF-16, FGF-4, FGF-17, FGF-5, FGF-19, FGF-6, FGF-20, FGF-8, FGF-21, FGF-9, FGF-23, FGF-10, KGF/FGF-7, FGF-11, FGF R1, FGF R4, FGF R2, FGF R5, FGF R3, Neuropilin-1, Neuropilin-2, Semaphorin 3A, Semaphorin 6B, Semaphorin 3C, Semaphorin 6C, Semaphorin 3E, Semaphorin 6D, Semaphorin 6A, Semaphorin 7A, MMP, MMP-11, MMP-1, MMP-12, MMP-2, MMP-13, MMP-3, MMP-14, MMP-7, MMP-15, MMP-8, MMP-16/MT3-MMP, MMP-9, MMP-24/MT5-MMP, MMP-10, MMP-25/MT6-MMP, TIMP-1, TIMP-3, TIMP-2, TIMP-4, ACE, IL-13 R alpha 1, IL-13, C1q R1/CD93, Integrin alpha 4/CD49d, VE-Cadherin, Integrin beta 2/CD18, CD31/PECAM-1, KLF4, CD36/SR-B3, LYVE-1, CD151, MCAM, CL-P1/COLEC12, Nectin-2/CD 112, Coagulation Factor III/Tissue Factor, E-Selectin, D6, P-Selectin, DC-SIGNR/CD299, SLAM, EMMPRIN/CD147, Tie-2, Endoglin/CD105, TNF RI/TNFRSF1A, EPCR, TNF RII/TNFRSF1B, Erythropoietin R, TRAIL R1/TNFRSF10A, ESAM, TRAIL R2/TNFRSF10B, FABP5, VCAM-1, ICAM-1/CD54, VEGF R2/Flk-1, ICAM-2/CD102, VEGF R3/Flt-4, IL-1 RI and VG5Q.
Other embodiments of the method provide multivalent binding proteins wherein at least one of binding domain 1 and binding domain 2 specifically binds a target selected from the group consisting of Prostate-specific Membrane Antigen (Folate Hydrolase 1), Epidermal Growth Factor Receptor (EGFR), Receptor for Advanced Glycation End products (RAGE, also known as Advanced Glycosylation End product Receptor or AGER), IL-17 A, IL-17 F, P19 (IL23A and IL12B), Dickkopf-1 (Dkk1), NOTCH1, NG2 (Chondroitin Sulfate ProteoGlycan 4 or CSPG4), IgE (IgHE or IgH2), IL-22R (IL22RA1), IL-21, Amyloid β oligomers (Ab oligomers), Amyloid β Precursor Protein (APP), NOGO Receptor (RTN4R), Low Density LipoproteinReceptor-Related Protein 5 (LRP5), IL-4, Myostatin (GDF8), Very Late Antigen 4, an alpha 4, beta 1 integrin (VLA4 or ITGA4), an alpha 4, beta 7 integrin found on leukocytes, and IGF-1R. For example, a VLA4 target may be recognized by a multivalent binding protein in which at least one of binding domain 1 and binding domain 2 is a binding domain derived from Natalizumab (Antegren).
In some embodiments, the cancer cell is a transformed, or cancerous, hematopoietic cell. In certain of these embodiments, at least one of the first binding domain and the second binding domain recognizes a target selected from the group consisting of a B-cell target, a monocyte/macrophage target, a dendritic cell target, an NK-cell target and a T-cell target, each as herein defined. Further, at least one of the first binding domain and the second binding domain can recognize a myeloid targets, including but not limited to, CD5, CD10, CD11b, CD11c, CD13, CD14, CD15, CD18, CD19, CD20, CD21, CD22, CD23, CD25, CD27, CD29, CD30, CD31, CD33, CD34, CD35, CD38, CD43, CD45, CD64, CD66, CD68, CD70, CD80, CD86, CD87, CD88, CD89, CD98, CD100, CD103, CD111, CD112, CD114, CD115, CD116, CD117, CD118, CD119, CD120a, CD120b, CDw123, CDw131, CD141, CD162, CD163, CD 177, CD312, TRTA 1, IRTA2, IRTA3, IRTA4, IRTA5, B-B2, B-B8 and B-cell antigen receptor.
Other embodiments of the invention are drawn to the multivalent binding protein, as described herein, comprising a sequence selected from the group consisting of SEQ ID NOS:2, 4, 6, 103, 105, 107, 109, 332, 333, 334, and 345. Other embodiments are directed to the multivalent binding protein comprising a sequence selected from the group consisting of SEQ ID NOS:355, 356, 357, 358, 359, 360, 361, 362, 363, 364 and 365.
In other embodiments, the multivalent and multispecific binding protein with effector function has a first binding domain and a second binding domain that recognize a target pair selected from the group consisting of EPHB4-KDR and TIE-TEK. In such embodiments, the protein has a first binding domain recognizing EPHB4 and a second binding domain recognizing KDR or a first binding domain recognizing KDR and a second binding domain recognizing EPHB4. Analogously, the protein may have a first binding domain recognizing TIE and a second binding domain recognizing TEK, or a first binding domain recognizing TEK and a second binding domain recognizing TIE.
In a related aspect, the invention provides a multivalent binding protein with effector function, wherein the constant sub-region recognizes an effector cell FC receptor (e.g., FCγRI, FCγRII, FCγRIII, FCαR, and FCεRI. In particular embodiments, the constant sub-region recognizes an effector cell surface protein selected from the group consisting of CD2, CD3, CD16, CD28, CD32, CD40, CD56, CD64, CD89, FCεRI, KIR, thrombospondin R, NKG2D, 2B4/NAIL and 41BB. The constant sub-region may comprise a CH2 domain and a CH3 domain derived from the same, or different, immunoglobulins, antibody isotypes, or allelic variants. In some embodiments, the CH3 domain is truncated and comprises a C-terminal sequence selected from the group consisting of SEQ ID NOS: 366, 367, 368, 369, 370 and 371. Preferably, the CH2 domain and the scorpion linker are derived from the same class, or from the same sub-class, of immunoglobulin, when the linker is a hinge-like peptide derived from an immunoglobulin.
Some proteins according to the invention are also contemplated as further comprising a scorpion linker of at least about 5 amino acids attached to the constant sub-region and attached to the second binding domain, thereby localizing the scorpion linker between the constant sub-region and the second binding domain. Typically, the scorpion linker peptide length is between 5-45 amino acids. Scorpion linkers include hinge-like peptides derived from immunoglobulin hinge regions, such as IgG1, IgG2, IgG3, IgG4, IgA, and IgE hinge regions. Preferably, a hinge-like scorpion linker will retain at least one cysteine capable of forming an interchain disulfide bond under physiological conditions. Scorpion linkers derived from IgG1 may have 1 cysteine or two cysteines, and will preferably retain the cysteine corresponding to an N-terminal hinge cysteine of IgG1. In some embodiments, the scorpion linker is extended relative to a cognate immunoglobulin hinge region and, in exemplary embodiments, comprises a sequence selected from the group consisting of SEQ ID NOS:351, 352, 353 and 354. Non-hinge-like peptides are also contemplated as scorpion linkers, provided that such peptides provide sufficient spacing and flexibility to provide a single-chain protein capable of forming two binding domains, one located towards each protein terminus (N and C) relative to a more centrally located constant sub-region domain. Exemplary non-hinge-like scorpion linkers include peptides from the stalk region of type II C-lectins, such as the stalk regions of CD69, CD72, CD94, NKG2A and NKG2D. In some embodiments, the scorpion linker comprises a sequence selected from the group consisting of SEQ ID NOS:373, 374, 375, 376 and 377.
The proteins may also comprise a linker of at least about 5 amino acids attached to the constant sub-region and attached to the first binding domain, thereby localizing the linker between the constant sub-region and the first binding domain. In some embodiments, linkers are found between the constant sub-region and each of the two binding domains, and those linkers may be of the same or different sequence, and of the same or different lengths.
The constant sub-region of the proteins according to the invention provides at least one effector function. Any effector function known in the art to be associated with an immunoglobulin (e.g., an antibody) is contemplated, such as an effector function selected from the group consisting of antibody-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), relatively extended in vivo half-life (relative to the same molecule lacking a constant sub-region), FcR binding, protein A binding, and the like. In some embodiments, the extended half-lives of proteins of the invention are at least 28 hours in a human. Of course, proteins intended for administration to non-human subjects will exhibit relatively extended half-lives in those non-human subjects, and not necessarily in humans.
In general, the proteins (including polypeptides and peptides) of the invention exhibit a binding affinity of less than 10−9 M, or at least 10−6 M, for at least one of the first binding domain and the second binding domain.
Another aspect of the invention is drawn to a pharmaceutical composition comprising a protein as described herein and a pharmaceutically acceptable adjuvant, carrier or excipient. Any adjuvant, carrier, or excipient known in the art is useful in the pharmaceutical compositions of the invention.
Yet another aspect of the invention provides a method of producing a protein as described above comprising introducing a nucleic acid encoding the protein into a host cell and incubating the host cell under conditions suitable for expression of the protein, thereby expressing the protein, preferably at a level of at least 1 mg/liter. In some embodiments, the method further comprises isolating the protein by separating it from at least one protein with which it is associated upon intracellular expression. Suitable host cells for expressing the nucleic acids to produce the proteins of the invention include, but are not limited to, a host cell selected from the group consisting of a VERO cell, a HeLa cell, a CHO cell, a COS cell, a W138 cell, a BHK cell, a HepG2 cell, a 3T3 cell, a RIN cell, an MDCK cell, an A549 cell, a PC12 cell, a K562 cell, a HEK293 cell, an N cell, a Spodoptera frugiperda cell, a Saccharomyces cerevisiae cell, a Pichia pastoris cell, any of a variety of fungal cells and any of a variety of bacterial cells (including, but not limited to, Escherichia coli, Bacillus subtilis, Salmonella typhimurium, and a Streptomycete).
The invention also provides a method of producing a nucleic acid encoding the protein, as described above, comprising covalently linking the 3′ end of a polynucleotide encoding a first binding domain derived from an immunoglobulin variable region to the 5′ end of a polynucleotide encoding a constant sub-region, covalently linking the 5′ end of a polynucleotide encoding a scorpion linker to the 3′ end of the polynucleotide encoding the constant sub-region, and covalently linking the 5′ end of a polynucleotide encoding a second binding domain derived from an immunoglobulin variable region to the 3′ end of the polynucleotide encoding the scorpion linker, thereby generating a nucleic acid encoding a multivalent binding protein with effector function. Each of these coding regions may be separated by a coding region for a linker or hinge-like peptide as part of a single-chain structure according to the invention. In some embodiments, the method produces a polynucleotide encoding a first binding domain that comprises a sequence selected from the group consisting of SEQ 113 NO: 2 (anti-CD20 variable region, oriented VL-VH), SEQ ID NO: 4 (anti-CD28 variable region, oriented VL-VH) and SEQ ID NO: 6 (anti-CD28 variable region, oriented VH-VL) in single-chain form, rather than requiring assembly from separately encoded polypeptides as must occur for heteromultimeric proteins, including natural antibodies. Exemplary polynucleotide sequences encoding first binding domains are polynucleotides comprising any of SEQ ID NOS: 1, 3 or 5.
This aspect of the invention also provides methods for producing encoding nucleic acids that further comprise a linker polynucleotide inserted between the polynucleotide encoding a first binding domain and the polynucleotide encoding a constant sub-region, the linker polynucleotide encoding a peptide linker of at least 5 amino acids. Additionally, these methods produce nucleic acids that further comprise a linker polynucleotide inserted between the polynucleotide encoding a constant sub-region and the polynucleotide encoding a second binding domain, the linker polynucleotide encoding a peptide linker of at least 5 amino acids. Preferably, the encoded peptide linkers are between 5 and 45 amino acids.
The identity of the linker regions present either between BD1 and EFD or EFD and BD2 may be derived from other sequences identified from homologous −Ig superfamily members. In developing novel linkers derived from existing sequences present in homologous members of the −Ig superfamily, it may be preferable to avoid sequence stretches similar to those located between the end of a C-like domain and the transmembrane domain, since such sequences are often substrates for protease cleavage of surface receptors from the cell to create soluble forms. Sequence comparisons between different members of the −Ig superfamily and subfamilies can be compared for similarities between molecules in the linker sequences that join multiple V-like domains or between the V and C like domains. From this analysis, conserved, naturally occurring sequence patterns may emerge; these sequences when used as the linkers between subdomains of the multivalent fusion proteins should be more protease resistant, might facilitate proper folding between Ig loop regions, and would not be immunogenic since they occur in the extracellular domains of endogenous cell surface molecules.
The nucleic acids themselves comprise another aspect of the invention. Contemplated are nucleic acids encoding any of the proteins of the invention described herein. As such, the nucleic acids of the invention comprise, in 5′ to 3′ order, a coding region for a first binding domain, a constant sub-region sequence, and a coding region for a second binding domain. Also contemplated are nucleic acids that encode protein variants wherein the two binding domains and the constant sub-region sequences are collectively at least 80%, and preferably at least 85%, 90%, 95%, or 99% identical in amino acid sequence to the combined sequences of a known immunoglobulin variable region sequence and a known constant sub-region sequence. Alternatively, the protein variants of the invention are encoded by nucleic acids that hybridize to a nucleic acid encoding a non-variant protein of the invention under stringent hybridization conditions of 0.015 M sodium chloride, 0.0015 M sodium citrate at 65-68° C. or 0.015 M sodium chloride, 0.0015 M sodium citrate, and 50% formamide at 42° C. Variant nucleic acids of the invention exhibit the capacity to hybridize under the conditions defined immediately above, or exhibit 90%, 95%, 99%, or 99.9% sequence identity to a nucleic acid encoding a non-variant protein according to the invention.
In related aspects, the invention provides a vector comprising a nucleic acid as described above, as well as host cells comprising a vector or a nucleic acid as described herein. Any vector known in the art may be used (e.g., plasmids, phagemids, phasmids, cosmids, viruses, artificial chromosomes, shuttle vectors and the like) and those of skill in the art will recognize which vectors are particularly suited for a given purpose. For example, in methods of producing a protein according to the invention, an expression vector operable in the host cell of choice is selected. In like manner, any host cell capable of being genetically transformed with a nucleic acid or vector of the invention is contemplated. Preferred host cells are higher eukaryotic host cells, although lower eukaryotic (e.g., yeast) and prokaryotic (bacterial) host cells are contemplated.
Another aspect of the invention is drawn to a method of inducing damage to a target cell comprising contacting a target cell with a therapeutically effective amount of a protein as described herein. In some embodiments, the target cell is contacted in vivo by administration of the protein, or an encoding nucleic acid, to an organism in need. Contemplated within this aspect of the invention are methods wherein the multivalent single-chain binding protein induces an additive amount of damage to the target cell, which is that amount of damage expected from the sum of the damage attributable to separate antibodies comprising one or the other of the binding domains. Also contemplated are methods wherein the multivalent single-chain binding protein induces a synergistic amount of damage to the target cell compared to the sum of the damage induced by a first antibody comprising the first binding domain but not the second binding domain and a second antibody comprising the second binding domain but not the first binding domain. In some embodiments, the multivalent single-chain binding protein is multispecific and comprises a binding domain pair specifically recognizing a pair of antigens selected from the group consisting of CD19/CD20, CD20/CD21, CD20/CD22, CD20/CD40, CD20/CD79a, CD20/CD79b, CD20/CD81, CD21/CD79b, CD37/CD79b, CD79b/CD81, CD19/CL H (i.e., MHC class II), CD20/CL II, CD30/CL II, CD37/CL II, CD72/CL II, and CD79b/CL II.
This aspect of the invention also comprehends methods wherein the multispecific, multivalent single-chain binding protein induces an inhibited amount of damage to the target cell compared to the sum of the damage induced by a first antibody comprising the first binding domain but not the second binding domain and a second antibody comprising the second binding domain but not the first binding domain. Exemplary embodiments include methods wherein the multi-specific, multivalent single-chain binding protein comprises a binding domain pair specifically recognizing a pair of antigens selected from the group consisting of CD20/CL II, CD21/CD79b, CD22/CD79b, CD40/CD79b, CD70/CD79b, CD72/CD79b, CD79a/CD79b, (D79b/CD80, CD79b/CD86, CD21/CL II, CD22/CL II, CD23/CL II, CD40/CL II, CD70/CL II, CD80/CL II, CD86/CL II, CD19/CD22, CD20/CD22, CD21/CD22, CD22/CD23, CD22/CD30, CD22/CD37, CD22/CD40, CD22/CD70, CD22/CD72, CD22/79a, CD22/79b, CD22/CD80, CD22/CD86 and CD22/CL II.
In a related aspect, the invention provides a method of treating a cell proliferation disorder, e.g., cancer, comprising administering a therapeutically effective amount of a protein (as described herein), or an encoding nucleic acid, to an organism in need. Those of skill in the art, including medical and veterinary professionals, are proficient at identifying organisms in need of treatment. Disorders contemplated by the invention as amenable to treatment include a disorder selected from the group consisting of a cancer, an autoimmune disorder, Rous Sarcoma Virus infection and inflammation. In some embodiments, the protein is administered by in vivo expression of a nucleic acid encoding the protein as described herein. The invention also comprehends administering the protein by a route selected from the group consisting of intravenous injection, intraarterial injection, intramuscular injection, subcutaneous injection, intraperitoneal injection and direct tissue injection.
Another aspect of the invention is directed to a method of ameliorating a symptom associated with a cell proliferation disorder comprising administering a therapeutically effective amount of a protein, as described herein, to an organism in need. Those of skill in the art are also proficient at identifying those disorders, or diseases or conditions, exhibiting symptoms amenable to amelioration. In some embodiments, the symptom is selected from the group consisting of pain, heat, swelling and joint stiffness.
Yet another aspect of the invention is drawn to a method of treating an infection associated with an infectious agent comprising administering a therapeutically effective amount of a protein according to the invention to a patient in need, wherein the protein comprises a binding domain that specifically binds a target molecule of the infectious agent. Infectious agents amenable to treatment according to this aspect of the invention include prokaryotic and eukaryotic cells, viruses (including bacteriophage), foreign objects, and infectious organisms such as parasites (e.g., mammalian parasites).
A related aspect of the invention is directed to a method of ameliorating a symptom of an infection associated with an infectious agent comprising administering an effective amount of a protein according to the invention to a patient in need, wherein the protein comprises a binding domain that specifically binds a target molecule of the infectious agent. Those of skill in the medical and veterinary arts will be able to determine an effective amount of a protein on a case-by-case basis, using routine experimentation.
Yet another related aspect of the invention is a method of reducing the risk of infection attributable to an infectious agent comprising administering a prophylactically effective amount of a protein according to the invention to a patient at risk of developing the infection, wherein the protein comprises a binding domain that specifically binds a target molecule of the infectious agent. Those of skill in the relevant arts will be able to determine a prophylactically effective amount of a protein on a case-by-case basis, using routine experimentation.
Another aspect of the invention is drawn to the above-described multivalent single-chain binding protein wherein at least one of the first binding domain and the second binding domain specifically binds an antigen selected from the group consisting of CD19, CD20, CD21, CD22, CD23, CD30, CD37, CD40, CD70, CD72, CD79a, CD79b, CD80, CD81, CD86, and a major histocompatibility complex class II peptide.
In certain embodiments, one of the first binding domain and the second binding domain specifically binds CD20, and in some of these embodiments, the other binding domain specifically binds an antigen selected from the group consisting of CD19, CD20, CD21, CD22, CD23, CD30, CD37, CD40, CD70, CD72, CD79a, CD79b, CD80, CD81, CD86, and a major histocompatibility complex class II peptide. For example, in one embodiment, the first binding domain is capable of specifically binding CD20 while the second binding domain is capable of specifically binding, e.g., CD19. In another embodiment, the first binding domain binds CD19 while the second binding domain binds CD20. An embodiment in which both binding domains bind CD20 is also contemplated.
In certain other embodiments according to this aspect of the invention, one of the first binding domain and the second binding domain specifically binds CD79b, and in some of these embodiments, the other binding domain specifically binds an antigen selected from the group consisting of CD19, CD20, CD21, CD22, CD23, CD30, CD37, CD40, CD70, CD72, CD79a, CD79b, CD80, CD81, CD86, and a major histocompatibility complex class II peptide. Exemplary embodiments include distinct multi-specific, multivalent single-chain binding proteins in which a first binding domain:second binding domain specifically binds CD79b:CD19 or CD19:CD79b. A multivalent binding protein having first and second binding domains recognizing CD79b is also comprehended.