Lytic antibodies elicited by Trypanosoma cruzi infection recognize epitopes present on both bloodstream trypomastigote and epimastigote forms of parasite

Abstract

SUMMARYSera of Chaga's disease patients containing anti-T. cruzi lytic antibodies were submitted to affinity chromatography using Sepharose 4B conjugated with antigen extracted from epimastigote or trypomastigote forms of the parasite. Epimastigotes were obtained from culture at the exponential growth phase and the trypomastigotes from blood of infected and immunosuppressed mice. Antigen of both parasite forms was obtained by sonication of the parasites followed by cemrifugation. Both antigens were then conjugated to activated Sepharose 4B. Affinity chromatography was performed by passing sera from chagasic patients through an immunoadsorbent column containing either epimastigote or trypomasugote antigens. Antibodies bound to the column were eluted with cold 0,2 M glycine buffer pH 2,8. The eluted antibodies were analysed regarding their isotype and lytic activity. The results showed that anti-T. cruzi lytic antibodies present in sera from chagasic patients are mainly located in the IgG isotype and recognize epitopes present in both trypomastigote and epimastigote forms. A brief report of this work has already been published 12 .

Carbohydrate immunity in American trypanosomiasis

“…The antibody targets in these forms, however, probably involve structurally different cell surface components. Although whole epimastigotes do not absorb lytic antibodies from Chagasic patients, Sepharose-conjugated epimastigote extracts, obtained by sonication/centrifugation, do [88]. Factors influencing trypanolysis depend on (a) the concentration of lytic antibodies in relation to the number of parasites: (b) intrinsic properties of different strains and cultures of trypomastigotes as well as of parasites from different sources, and (c) modulation of parasite surface antigens or epitopes as a function of the parasite biosynthetic and antigen-expression mechanisms.…”