Chemistry: natural resins or derivatives; peptides or proteins; – Peptides of 3 to 100 amino acid residues
Reexamination Certificate
1999-07-16
2002-10-01
Devi, S. (Department: 1645)
Chemistry: natural resins or derivatives; peptides or proteins;
Peptides of 3 to 100 amino acid residues
C530S350000, C530S822000, C530S806000, C435S007220, C435S975000, C424S269100, C424S265100, C424S266100, C424S185100
Reexamination Certificate
active
06458922
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to sets of at least 6 recombinant and/or synthetic peptides derived from
Trypanosoma cruzi
proteins which are used for diagnosing Chagas' disease in a highly sensitive and specific manner. More specifically, the present invention relates to peptides derived from the
T. cruzi
antigens SAPA, CRA, FRA, TcD, Tc24, Ag39 and MAP which are used in a confirmatory immunoassay and concerns kits comprising the latter peptides.
BACKGROUND OF THE INVENTION
Chagas' disease is endemic throughout Latin America and a major cause of morbidity and mortality in those countries affected. Approximately 16-18 million people are infected, and about 50,000 patients die each year from the condition (Carvalho et al., 1993). Its etiologic agent, the protozoan parasite
Trypanosoma cruzi,
is naturally transmitted by various species of triatomine bugs. Disease transmission occurs when infectious forms of the parasite are deposited during the blood meal along with the insect's feces. In Brazil, successful vector control programs have almost completely abolished naturally occurring transmission, with the exception of the hinterland. As a result, transfusion of blood from infected donors—often migrants to larger cities—has become the major route for contracting the parasite (Almeida et al., 1990). Recent surveys estimate the annual number of transfusion-acquired Chagas' disease cases in Brazil at 20,000 out of a total of 5 to 6 million blood transfusions (Zingales et al., 1990). Consequently, an efficient donor screening program is crucial in eliminating contaminated blood while not negatively affecting the country's blood supply.
In Brazilian blood banks, the screening for antibodies directed against
T. cruzi
is mandatory. Screening assays include indirect immunofluorescence (IFA), indirect hemagglutination (IHA), and enzyme-linked immunosorbent assays (ELISA). The utilization of at least two assays based on either different methodologies or different antigen preparations is currently recommended, but conflicting results are often observed. A few specialized laboratories have developed Western blot techniques (Peralta et al., 1994) in an attempt to resolve discrepant results, but no single test is sufficiently sensitive to prevent transfusion transmission of Chagas' disease.
Most of the tests that are commercially available today employ crude parasite extracts or subcellular fractions as antigen preparations. However, it has been shown that parasite extracts cross-react with sera from patients harboring other diseases such as leishmaniasis,
Trypanosoma rangeli
infection, syphilis, or rheumatic fever. In recent years, various investigators have reported the cloning and characterization of
T. cruzi
-specific immunoreactive antigens (Borges-Pereira, 1997). Several studies have evaluated the diagnostic potential of these recombinant antigens either in the form of fusion proteins or as synthetic peptides (Almeida et al., 1990; Peralta et al., 1994). Although an increase in sensitivity and specificity of these assays was observed, cross-reactivity with Leishmania-specific antibodies still occurred. The present invention relates to sets of at least 6 recombinant and/or synthetic peptides derived from
Trypanosoma cruzi
antigens which are used for diagnosing Chagas's disease in a highly sensitive and specific manner and which do not cross react with Leishmania-specific antibodies. The use of a new multiparameter assay combining relevant and immunodominant antigens derived from
T. cruzi
proteins as a diagnostic test for Chagas' disease is herein described.
AIMS OF THE INVENTION
It is clear from the above that no single test is sufficiently sensitive to prevent transfusion transmission of Chagas' disease which has become the major route of transmission for this infection. Current screening tests are insensitive, non-specific and yield conflicting results, while convenient confirmatory assays do not exist. The present invention therefore aims at providing sets of recombinant and/or synthetic antigens and their use for serological diagnosis of Chagas' disease. More specifically, the present invention aims at providing assays which are able to reliably and accurately detect the presence of antibodies to various specific antigens of
Trypanosoma cruzi
in a highly sensitive and specific manner. In this regard, the present invention aims at providing sets of at least 6 recombinant and/or synthetic peptides derived from the
T. cruzi
antigens SAPA, CRA, FRA, TcD, Tc24, Ag39 and MAP for usage in a confirmatory immunoassay and aims at providing kits comprising the latter peptides. Moreover, it is also an aim of the present invention to provide sets of
T. cruzi
antigens which can be used in a vaccine composition for immunizing an individual to prevent Chagas' disease upon exposure to
T. cruzi.
REFERENCES:
patent: 5916572 (1999-06-01), Reed et al.
patent: WO9525797 (1995-09-01), None
patent: 9718475 (1997-05-01), None
Houghten et al. Vaccine86, Cold Spring Harbor Laboratory, pp. 21-25, 1986.*
Lorca et al. Revista Medica De Chile 121: 363-368, 1993, abstract.*
Engman et al. J. Biol. Chem. 264: 18627-18631, 1989.*
Lafaille et al. Mol. Biochem. Parasitol. 35: 127-136, 1989.*
Cotrim et al. J. Clin. Microbiol. 28: 519-524, 1990.*
Burns et al. PNAS 89: 1239-1243, 1992.*
Ibanez et al. Mol. Biochem. Parasitol. 30: 27-34, 1988.*
Pollevick et al. Mol. Biochem. Parasitol. 47:247-250, 1991.*
Buschiazzo et al. Mol. Biochem. Parasitol. 54: 125-128, 1992.*
Almeida et al. Mem. Inst. Oswaldo Cruz. 85: 513-517, 1990.*
Pastini, et al., “Immunoassay . . . Chagas Disease”, Clin. Chem., vol. 40, No. 10, 1994, pp. 1893-1897.
Vergara et a;. “Assay . . . Synthetic Peptides”, J. Clin. Microbiol., vol. 29, No. 9, 1991, pp. 2034-2037.
Devi S.
Innogenetics N.V.
LandOfFree
Antigens and immunoassays for diagnosing Chagas' disease does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Antigens and immunoassays for diagnosing Chagas' disease, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Antigens and immunoassays for diagnosing Chagas' disease will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2976415