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  Neospora caninum isolateUSPTO Application #: 20080107645Title: Neospora caninum isolate Abstract: The present invention relates to a novel Neospora caninum isolate from Nowra and extracts thereof. The strain is useful in the development of diagnostic assays for the detection of parasites in animals. The present invention also relates to pharmaceutical compositions, using live or killed organisms or extracts thereof, for the treatment and prevention of parasitic infections in animals. (end of abstract) Agent: Nixon & Vanderhye, Pc - Arlington, VA, US Inventors: John Timothy Ellis, Catherine Margaret Douglas Miller, Helen Elizabeth Ouinn USPTO Applicaton #: 20080107645 - Class: 424130100 (USPTO) Related Patent Categories: Drug, Bio-affecting And Body Treating Compositions, Immunoglobulin, Antiserum, Antibody, Or Antibody Fragment, Except Conjugate Or Complex Of The Same With Nonimmunoglobulin Material The Patent Description & Claims data below is from USPTO Patent Application 20080107645. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] The present invention relates to a novel parasitic protozoan isolate and extracts thereof. The strain is useful in the development of diagnostic assays for the detection of parasites in animals. The present invention also relates to pharmaceutical compositions, using live organisms or extracts thereof, for the treatment and prevention of parasitic infections in animals. BACKGROUND OF THE INVENTION [0002] The Apicomplexa is a diverse phylum of protozoa containing some of the most pathogenic organisms known to man. Representatives include taxa of the well known genera such as Plasmodium, Babesia and Toxoplasma. In 1984 a research group in Norway reported a previously unknown cyst-forming protozoan which caused encephalitis and myositis in dogs (Bjerkas et al. 1984). These clinical signs were consistent with those caused by Toxoplasma gondii, a widely distributed member of the Apicomplexa. However, unlike T. gondii, the organism was not pathogenic to outbred mice, nor were T. gondii specific antibodies present in the sera of the dogs studied. This prompted further investigation which demonstrated conclusively the organism was ultrastructurally and antigenically distinct from T. gondii (Dubey et al. 1988). Neospora caninum was thus described as a new member of the Sarcocystidae. Soon after, N. caninum was implicated as a cause of abortion in cattle (Thilstead & Dubey, 1989). [0003] An increasing number of N. caninum isolates have now been obtained, using techniques involving predominantly the direct inoculation of infected tissues onto tissue culture cells (Dubey et al. 1988, Conrad et al. 1993), although bovine isolates have proven difficult to obtain. The primary reason for this has been the detrimental effects of autolysis on the viability of N. caninum in aborted bovine fetal tissues. The isolation of a parasite population from a live animal is therefore preferred. [0004] Recent studies on the biological properties of bovine and canine isolates have suggested they belong to a single species called N. caninum (Holmdahl et al. 1997), despite the record that wide differences exist between isolates in their biological properties. These include differences in antigenicity, ultrastructure, pathogenicity and genetic heterogeneity (Conrad et al. 1993, Marsh et al. 1995, Lindsay et al. 1995 and Atkinson et al. 1999). Thus not all isolates of N. caninum may possess the same properties, and indeed at least one isolate of N. caninum was mistakenly identified as Hammondia heydorni previously (Schares et al. 2001). Indeed, others have speculated on whether N. caninum and H. heydorni are the same or different species (Mehlhorn and Heydorn, 2000). Hammondia heydorni is also a cyst-forming coccidian that has a life cycle which is very similar to that of N. caninum. Thus the true identity of the species N. caninum is currently being debated, and its relationship to H. heydorni is unclear. [0005] In cattle, abortion due to N. caninum infections usually occur in midto late gestation, although not all infected foetuses are aborted. Many congenitally infected calves are born healthy and persistently infected, although some infected calves are diseased at birth and die in the neonatal period with lesions similar to those of aborted calves. [0006] The development and use of serological tests for the diagnosis of neosporosis in livestock, along with the identification of animals infected or exposed to N. caninum, has been reviewed previously in great detail (Bjorkman et al. 1999; Atkinson et al. 2000a). Significantly, however, there is no effective vaccine against transplacental transmission or foetal loss which occurs as a result of neosporosis and attempts to formulate a vaccine have met with limited success. [0007] Liddel et al. (1999) injected female BALB/c mice with a crude N. caninum tachyzoite lysate preparation co-administered with ImmuMAXSR.TM. adjuvant. These mice were subsequently mated, and pregnant dams were challenged with N. caninum tachyzoites at 10-12 days of gestation. Results showed a single injection offered complete protection against transplacental transmission of the parasite to the pups. All pups in this experimental group were free from parasitic infection. No results have yet been reported on the efficacy of this vaccine formulation in the bovine. [0008] Baszler et al. (2000) examined the possibility of vaccination of BALB/c mice with soluble N. caninum antigen formulated in either nonionic surfactant vesicles or Freunds Complete Adjuvant. This approach resulted in exacerbation of encephalitis and neurological disease in these mice. These observations were characterised by increased antigen specific IL-4 secretion and increased IgG1:IgG2a ratios in vivo. [0009] Adrianarivo et al. (1999) tested four different adjuvants with a killed whole N. caninum tachyzoite preparation for immunogenicity. The results indicated that the immune responses, as determined by IFAT titres, were significantly higher in experimentally infected cattle compared to immunised cattle. [0010] Adrianarivo et al. (2000) studied the effect of a killed N. caninum tachyzoite preparation in pregnant cattle using a POLYGEN.TM. adjuvant. Heifers were injected at day 35 and day 65 of gestation and four weeks later were challenged with intravenous or intramuscular injection of tachyzoites. Post immunisation, heifers developed both humoral and cell mediated immune responses characterised by an increase in production of IgG1 and IFN-.gamma. respectively. Following a challenge with N. caninum tachyzoites, however, significant cell mediated immune response did not occur. All foetuses in the study, both from control and experimental cattle, developed lesions characteristic of N. caninum infection. Failure to prevent foetal infection by this formulation in pregnant cattle was concluded. [0011] Unlike the development of killed or genetically engineered vaccines against parasites, vaccines based on live populations of parasites are available, for example against Toxoplasma-induced abortion in sheep (Buxton & Innes, 1995) and Eimeria parasites of poultry (Shirley & Bedrnik, 1997). A live vaccine is not, however, available against N. caninum. [0012] The literature on live vaccines against N. caninum is limited. Atkinson et al. (1999) showed that infection of naive mice by the Nc-SweB1 isolate of N. caninum partially protected them against a severe infection by Nc-Liverpool. Lindsay et al. (1999) generated temperature sensitive mutants of N. caninum and demonstrated that they could prevent clinical signs associated with neosporosis in mice. SUMMARY OF INVENTION [0013] The present inventors have isolated a novel protozoan parasite from the central nervous system of a dairy calf. The parasite was identified based on a number of criteria as an isolate of Neospora caninum and was called the "Nc-Nowra" strain. This isolate is naturally attenuated in its ability to cause neosporosis in a laboratory animal, and thus is an ideal isolate to serve as a basis for a vaccine against this disease. [0014] A sample of the Nc-Nowra isolate was deposited under the provisions of the Budapest Treaty on 21 Jun. 2001 with the Australian Government Analytical Laboratories (AGAL) and accorded AGAL Accession No NM01/22338. Further, a sample of Vero cells was deposited under the provisions of the Budapest Treaty on 21 Jun. 2001 with the Australian Government Analytical Laboratories (AGAL) and accorded AGAL Accession No NM01/22339. [0015] Accordingly, in a first aspect the present invention provides a parasitic protozoan isolate having the characteristics of the isolate deposited as AGAL Accession No. NM01/22338. [0016] In a preferred embodiment of the first aspect, the isolate is that deposited as AGAL Accession No. NM01/22338. [0017] In a second aspect, the present invention provides an antibody raised against an isolate according to the first aspect. Preferably, the antibody is a monoclonal antibody. [0018] In a third aspect the present invention provides a host cell infected with an isolate of the first aspect. Preferably, the host cell is derived from the sample deposited as AGAL Accession No NM01/22339. [0019] In a fourth aspect, the invention provides a vaccine composition comprising an isolate of the first aspect, wherein the isolate is in the form of a killed parasite population or live attenuated parasites. [0020] The present invention also provides a vaccine composition comprising an extract or an isolate according to the first aspect. Preferably, the extract is selected from the group consisting of live attenuated, killed and fixed parasites, a cell lysate, an antigenic polypeptide and a polynucleotide encoding an antigenic polypeptide. [0021] In a fifth aspect, the present invention provides a method for the treatment or prevention of infection or disease in an animal, the method comprising administering to the animal a vaccine composition according to the fourth aspect. Continue reading... Full patent description for Neospora caninum isolate Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Neospora caninum isolate 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. 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