Antigenic analysis of bovine Sarcocystis spp. in Sri Lanka

Sarcocystis is an intracellular parasite, known to cause acute and chronic diseases in a variety of animal hosts, including cattle. Sarcocystis has also been reported as a zoonotic form and causes cysts in meat resulting in economic losses. This study was designed to characterize Sarcocystis antigens by molecular weight and to investigate the possibility of cross-reaction with related Apicomplexan Toxoplasma gondii.

Sarcocystis antigen was prepared by chemical lysis (10% Triton) of bradyzoites/cystozoites contained in tissue cysts. Healthy rabbits were inoculated with Sarcocystis (antigen and whole parasite) and Toxoplasma and antibodies were harvested after a month. A higher antibody titre was elicited by the inoculation of Sarcocystis cystozoites as opposed to the antigen. The latex agglutination test confirmed the presence of anti Toxoplasma antibodies in test serum and negated cross-reactivity between Sarcocystis and T. gondii at 1:100 serum dilution. Immunoblot results also did not support cross-reactivity. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and subsequent immunoblot analysis at 1:100 serum dilution revealed twelve antigenic bands, three of which were prominent. Out of these three, two were complex bands of ~ 66 kMW and above. The other was a single band of ~ 45 kMW. Monoclonal antibodies can be developed against these potent antigens for diagnostic purposes in the future.

Keywords: Antigens, cross-reactivity, protozoan parasite, Sarcocystis, Sri Lanka, Toxoplasma   

doi:10.4038/jnsfsr.v36i3.161  

Journal of the National Science Foundation of Sri Lanka 36 (3) 239-244