Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: 3/26/2004
Publication Date: 4/29/2005
Citation: Tuo, W., Fetterer, R.H., Davis, B., Jenkins, M.C., Dubey, J.P. 2005. In search of immunodominant neospora caninum antigens using immunologic and proteomics technologies. 15th Annual BARC Poster Day, p. 51.
Technical Abstract: N. caninum is an apicomplexan parasite that causes abortion in cattle. In the past decade, neosporosis has been recognized as an important cause of pregnancy loss in cattle worldwide. It was estimated that approximately 20% of all bovine abortions were due to neosporosis. N. caninum-associated abortion costs the cattle imdustry in excess of $35 million a year in the state of Calfiornia alone. while antobody responses have been well documented in N. caninum infected cows, N. caninum-stimulated cell-mediated immunity is poorly understood. Natural exposure to the parasite does not necessariy provide protection against neosporosis-associated pregnancy loss, in spite of the presence of N. caninum-specific antibody in circulation. The objective of this study was to identify immunodminant T helper cell antigens that may be used a vaccine candidate. N. caninum-specific T helper cell lines were establihed from oeripheral blood lymphocytes of N. caninum-infected Holstein cows. These T helper cell lines were used to define antigenicity of the N. caninum proteins fractionated by HPLC anion exchange chromatography. The results showed that proteins in HPLC fractions 1-3 had low or undetectable T-cell-stimulating activity, whereas proteins in fractions 4-6 had high stimulatory activity Fraction 5 contained the highest antigenic activity detected by all T cell line. Western blot analysis showed that fraction 5 contained 8-10 distinctive N. caninum protein bands recognized by the rabbit and boine antisera against N. caninum tachyzoites (NC-1 strain). It is possible that one or more of these T cell stimulating and cytokine-inducing N. caninum proteins are candidates for inclusion in a N. caninum vaccine. Research in progress includes purification and identification of the T cell stimulating N. caninum proteins using proteomics technologies. Supported by USDA, ARS, CRIS Project No 401-1265-140-71.