Abstract

The study was carried out to examine the ways that Trypanosoma evansi components interact with the host, by investigating the components of the parasite which acted as antigens during infection, and to study the dynamic of some of these antigens during infection. Such approach could help in identifying new diagnostic reagents, a better understanding of existing diagnostic methods and target antigen for production of vaccines. The antigenic components of intact and trypsin-treated T. evansi were identified using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting against sera from infected rabbits and rabbits immunized with a range of soluble parasite materials. A trypsin sensitive component of ~52 kDa which was cleaved from the parasite by the process of trypsinisation and produced a potent reaction to infection and immunization sera was selected for further study. This antigenic component was purified by electro-elution from acrylamide gels and monospecific antiserum was produced and used in an antigen-capture enzyme linked immunosorbent assay (ELISA). This antigen was found to be preserved between different variants and populations of T. evansi and reached a detectable level in the circulation of infected animals before the remission of the first parasitemia and was cleared from the circulation following successful chemotherapy. The antigen represents a good candidate for the diagnosis of infection with T. evansi and for developing a serologically-based test for monitoring the effectiveness of chemotherapy.

Key words: Trypanosoma evansi, invariant antigens, immunoblotting, dynamic, diagnosis.