| Blocking leukocyte emigration and inflammation by interfering with cd99/hec2 -> Monitor Keywords |
|
|
 
Blocking leukocyte emigration and inflammation by interfering with cd99/hec2Related Patent Categories: Drug, Bio-affecting And Body Treating Compositions, LymphokineBlocking leukocyte emigration and inflammation by interfering with cd99/hec2 description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070154450, Blocking leukocyte emigration and inflammation by interfering with cd99/hec2. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a Divisional of U.S. application Ser. No. 10/221,758, filed Mar. 27, 2003, which is a 371 National Phase of International Application Serial No. PCT/US01/07963, filed Mar. 13, 2001, which claims priority under 35 U.S.C. .sctn. 119(e) to provisional application Ser. No. 60/188,804, filed Mar. 13, 2000, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0003] This invention concerns anti-inflammatory processes, in particular modulating transendothelial migration of leukocytes, and compositions for blocking transendothelial migration of leukocytes. BACKGROUND OF THE INVENTION [0004] References cited throughout this specification by number are listed at the end of the Examples in the section "REFERENCES". [0005] Previous studies (1-12) have demonstrated a crucial role for platelet/endothelial cell adhesion molecule-1 [PECAM] in transendothelial migration [TEM] of neutrophils [PMN], monocytes [Mo], and natural killer [NK] cells. However, even under the most favorable circumstances, anti-PECAM reagents block only 80-90% of leukocyte influx. While this is as good or better a block of inflammation as has been achieved by targeting a single molecule, the residual 10-20% of leukocytes that are not blocked may represent a clinically significant population under chronic conditions. Furthermore, there are at least some inflammatory models in which PECAM does not appear to play a role. Most important for the present invention, there may be stages in TEM that are mediated by molecules other than PECAM, which await discovery. Leukocyte Migration in Inflammation [0006] Migration of leukocytes into a site of inflammation involves several steps mediated by several families of adhesion molecules. We have focused on the step of transendothelial migration [TEM] because it is the step at which leukocytes become irreversibly committed to entering the inflamed tissues. We have previously described the critical role of PECAM, expressed on the surfaces of all Mo and PMN and concentrated at the borders of endothelial cells, in TEM. Under the best-controlled conditions, anti-PECAM reagents block 80-90% of TEM in in vitro and in many in vivo models. However, there are consistently at least 10-20% of leukocytes that escape this blockade (1, 2, 4, 6, 8). Furthermore, at least one in vivo model has been described in which antibody against PECAM has no effect (9). Targeted deletion of PECAM results in mice with no significant defects in their acute inflammatory response (26). Therefore, mechanisms of TEM independent of PECAM exist. Knowing these mechanisms will lead to a better understanding of inflammation. Targeting these pathways may be a useful adjunct to anti-inflammatory therapies aimed at PECAM. Molecularly Dissectable Steps in Leukocyte Emigration [0007] The inflammatory response is a double-edged sword. Mobilization of leukocytes to a focus of inflammation is critical for the rapid resolution of infections and restoration of tissue damage resulting from a variety of injuries. On the other hand, most human pathology results from inflammation that is misdirected or prolonged with the result that host tissues are damaged. Common examples include the inflammatory arthropathies, pulmonary fibrosis, and atherosclerosis, which is currently viewed as a chronic inflammatory disease of the arterial wall (13). Therefore, much attention has been directed toward understanding inflammation at the molecular level in the hopes of being able to better regulate it. [0008] The process of leukocyte emigration has been dissected into a series of sequential adhesion events in the following working model [See FIG. 1]. We can divide leukocyte emigration into these steps because we have reagents that can block each one of these steps. There may be additional adhesion molecules awaiting discovery that interact at steps intermediate to or distal to these. Indeed, CD99 may be just such a molecule. [0009] Rolling. In the first step, some of the leukocytes entering a postcapillary venule in an area of inflammation leave the circulatory stream and adhere loosely, tentatively, and reversibly to the endothelial cell surfaces in a process aptly named "rolling." The selection family of adhesion molecules and their sialylated-Lewis.sup.x-decorated ligands appear to be primarily responsible for this initial interaction [reviewed in (14,15)]. Rolling leukocytes come into direct contact with the endothelium, exposing them to a variety of signals capable of promoting the next step--activating the leukocyte-specific integrins. The binding of leukocytes to E-selectin itself may be a sufficient signal (16). Alternatively or additionally, the leukocytes tethered by selectins are now in a position to be activated by platelet activating factor (17) or other lipid modulators (18), chemokines bound to endothelial surface glycosaminoglycans (19), soluble chemoattractants (20), or ligands that cross-link leukocyte CD31 (3, 21, 22). [0010] Adhesion. Upon activation of their integrins to the high affinity binding state, leukocytes cease rolling and adhere tightly to the endothelial surface. For monocytes and lymphocytes, which express integrins of the both .beta.1 and .beta.2 families, engagement by either integrin may suffice to promote attachment for subsequent transmigration (23). The identified counter-receptors for .beta.1 and .beta.2 integrin-mediated adhesion include ICAM-1, ICAM-2, and VCAM-1, members of the immunoglobulin gene superfamily. Leukocytes bound tightly to the luminal surface of the endothelial cell crawl rapidly to an intercellular junction, a process that requires successive cycles of adhesion and dis-adhesion, as the leukocytes attach at their forward ends and release at their rear. [0011] Transmigration. Upon reaching the junction, they insert pseudopods between tightly apposed endothelial cells and crawl through, in ameboid fashion, while retaining tight contacts with the endothelial cell. This step is referred to as diapedesis, transendothelial migration [TEM], or transmigration. Platelet/endothelial cell adhesion molecule-1 [PECAM, also known as CD31], a CAM of the immunoglobulin superfamily (24), expressed on the surfaces of leukocytes and platelets and concentrated in the borders between endothelial cells, is involved in this step. Contact between leukocyte PECAM and endothelial PECAM is crucial for the transmigration of the vast majority of neutrophils and monocytes in vitro (1) and in vivo (2,8). We can inhibit TEM in vitro and in vivo by administering agents that interfere with the homophilic interaction of leukocyte PECAM with endothelial PECAM. These include mAb that bind to PECAM domain 1 and/or 2 and block this critical site, or soluble recombinant PECAM-IgG chimeras containing at least domain 1, which competitively inhibit this interaction (4, 6, 25). Therefore, PECAM-dependent transmigration is a promising target for anti-inflammatory therapy. [0012] In summary, while we have learned a great deal about the molecules and mechanisms of leukocyte rolling and adhesion to the apical surface of endothelium (15, 46, 47), there is a big gap in our present knowledge of transendothelial migration. PECAM clearly plays an important role in TEM for most PMN and monocytes under most inflammatory conditions studied to date. The function of PECAM in mediating transmigration without affecting apical adhesion defines TEM as a separate step in leukocyte emigration. However, while PECAM is the only molecule that has been identified to play a unique role in TEM, it is clearly not the only molecule involved in TEM. CD99 [0013] CD99 was discovered and pursued independently by four separate sets of investigators. It was identified by geneticists as the only known human pseudoautosomal gene; its gene product defines the Xg(a+) blood type. Similar to the case with the Duffy blood group, Xg(a-) individuals lack CD99 on their RBC, but express it appropriately on other cell types. The gene is located on the distal end of the short arm of the X chromosome, a region involved in pairing with a short homologous region of the Y chromosome during meiosis. Due to this phenomenon, cross-over of these regions of the X and Y chromosome led to duplication of this gene on the Y chromosome and inheritance of this gene similar to an autosomal trait, hence the name "pseudoautosomal." In mice several genes have been identified to be inherited this way. CD99 is the only example in humans thus far. [0014] The surgical pathology literature is replete with references to CD99, since it was found to be a reliable marker to distinguish Ewing's sarcoma from other "small round blue cell" tumors. However, the function of the molecule on the surfaces of these tumors is completely unknown. Its function is best characterized on T cells, where it was found to be an alternative ligand to CD2 for the phenomenon of sheep red blood cell resetting. In addition, ligation of CD99 on thymocytes and T cells has been shown to play a costimulatory function in certain in vitro models. These latter two functions will be discussed in more detail below, since they are the most relevant to a role for CD99 in leukocyte transmigration. [0015] One of the problems confronting CD99 research is that several of the existing CD99 mAb only react with epitopes expressed by immature thymocytes; other mAbs react with only certain peripheral blood leukocyte types due to posttranslational modifications of the molecule. Of the few published reports about CD99 on leukocytes, none use the same cell type or the same antibody, making comparisons difficult. For example, the VI.sup.th International Leukocyte Typing Workshop chapter on CD99 states that CD99 is not expressed on monocytes or platelets. Furthermore, one of the major publications on CD99 states that the molecule is not expressed by granulocytes. [0016] The cDNA encoding CD99 predicts a type I transmembrane protein of 16.7 kd that spans the membrane once. There are no consensus N-linked glycosylation sites, but several sites for O-linked glycosylation, which accounts for 14 kd of its apparent molecular weight of 32 kd. Indeed, treatment with O-glycanase reduces its Mr to 18 kd (Aubrit et al., Eur. J. Immunol. 1989, 19:1431). There is a proline-rich region near the mature amino terminus and a stretch of five Gly-X-Y repeats following that. However, there are no proline residues in these repeats, making it extremely unlikely that it functions as a "collagen-like" protein. CD99 is not a member of any known protein family, nor is it remotely homologous to any known protein except for 48% homology to PBDX, the product of a gene located adjacent to CD99 on the X chromosome and involved in the expression of CD99 on erythrocytes (Ellis et al., Nature Genetic, 1994, 8:285). There are only two methionine residues and one cysteine residue (on the cytoplasmic side) in the molecule, consistent with difficulty with metabolic labeling using these amino acids (see, page 37). The single cytoplasmic tyrosine residue is predicted to be the first amino acid on the cytoplasmic surface of the membrane, making it unlikely that it will play a role in known phosphotyrosine signaling cascades. [0017] Gelin, et al. (EMBO J, 1989, 8:3252) found that while the majority of spontaneous sheep (and human) RBC adhesion to human T cells was mediated by CD2/LFA-3 interactions, significant residual adhesion took place in the presence of optimal CD2 blockade. This was due to interactions between CD99 on the T cell and some other molecules(s) on the RBC. Since RBC normally express CD99, the way this was demonstrated was to show that a) anti-CD99 mAb absorbed to the RBC did not block binding, while the same mAb bound to the T cells did, and b) normal T cells rosetted with Xg(a-) RBC that do not express CD99, as well as they did with Xg(a+) RBC, which express it. While the rosetting effect was small compared to the extent of rosetting by CD2, this demonstrates that CD99 is capable of adhesive interactions in a heterophilic manner. [0018] The other reports on CD99 that are potentially relevant to this project involve cross-linking CD99 on the surfaces of thymocytes or T cells. In the Jurkat T cell line, cross-linking surface-bound CD99 mAb with a polyclonal anti-mouse antibody led to a rapid (<30 min.) increase in the surface expression of LFA-1 (CD11a/CD18) and stimulation of LFA-1/ICAM-1-dependent homotypic aggregation (Hahn et al., J. Immunol. 1997; 159:2550). The same treatment of immature (CD4.sup.+CD8.sup.+) thymocytes led to a similar rapid increase in surface T cell receptor and MHC Class I expression, which was believed to come from intracellular pools (Choi et al., J. Immunol. 1998; 161:745). Experiments using peripheral blood T cells showed that extensive cross-linking of CD99 (by plate-bound mAb) provided a costimulatory signal for intracellular Ca.sup.++ flux, CD25 expression, and proliferation under conditions of suboptimal cross-linking by anti-CD3 (Waclavicek et al., J. Immunol. 1998; 161:4671; Wingett et al., Cell. Immunol. 1999; 193:17). In all of these instances, the effects of the anti-CD99 mAb were small compared to those achieved by activating classical costimulatory molecules such as CD28. However, they demonstrate that CD99 is capable of functioning as a signaling molecule, either directly or indirectly, upon engagement. [0019] The ligand(s) for CD99 are not known. Since it is not a member of any known molecular family, it is impossible to make first guesses about its ligands and mechanisms of action based on experience with related family members. [0020] The present invention sheds more light on the process of transmigration, and on the function of CD99. In so doing, it elucidates an important inflammatory mechanism, and thus a strategy for modulating inflammation. Continue reading about Blocking leukocyte emigration and inflammation by interfering with cd99/hec2... Full patent description for Blocking leukocyte emigration and inflammation by interfering with cd99/hec2 Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Blocking leukocyte emigration and inflammation by interfering with cd99/hec2 patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Blocking leukocyte emigration and inflammation by interfering with cd99/hec2 or other areas of interest. ### Previous Patent Application: Linear polyethylenimine-sterol conjugates for gene delivery Next Patent Application: Methods and compositions using substance p to promote wound healing Industry Class: Drug, bio-affecting and body treating compositions ### FreshPatents.com Support Thank you for viewing the Blocking leukocyte emigration and inflammation by interfering with cd99/hec2 patent info. IP-related news and info Results in 0.16089 seconds Other interesting Feshpatents.com categories: Qualcomm , Schering-Plough , Schlumberger , Seagate , Siemens , Texas Instruments , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
