REACTIVITY OF CHAGASIC SERA WITH CRUDE AND HIGHLY PURIFIED GLYCOSPHINGOLIPID FRACTIONS FROM TRYPANOSOMA-CRUZI EPIMASTIGOTES

The reactivities of sera from patients with Chagas disease or from T. cruzi-immunized rabbits with two different lipid preparations of T. cr uziwere assessed using epimastigote antigens. Serum reactivities were determined using a quantitative enzyme-linked immunosorbent assay (ELI SA). Antigen 1 represents the lower phase obtained from crude lipid ex tract after Folch partition (LCL). Antigen 2 is a highly purified glyc osphingolipid fraction (GSL). The LCL antigen discriminated quite well the reactivities of Chagasic patients' sera and sera from healthy ind ividuals, as well as between the serum from a T. cruzi-immunized rabbi t (TIRS) and normal rabbit serum (NRS). A strong reactivity with GSL w as obtained with TIRS. Reactivity with GSL was also obtained with huma n Chagasic sera. Compared to a group of normal individuals, the reacti ons of antibodies directed against lipid antigens were considerably in creased in sera of patients with Chagas disease. Chagasic sera did not differentiate between glycolipids with terminal beta-glucosyl or beta -galactosyl nonreducing units. They discriminated, however, glucosylce ramides with differences in the ceramide structure. To determine the s pecificity of Chagasic sera, antibodies isolated on LCL-immunosorbent (LCL-Ch Abs) as well as on laminin-immunosorbent (Lam-Ch Abs) were tes ted against laminin and LCL antigens. We found that Lam-Ch Abs reacted with murine laminin, whereas the reaction was negative with LCL. In c ontrast, the LCL-Ch Abs reacted either with LCL antigens or with lamin in. The reactivity with laminin was strong in comparison with LCL. Res ults suggest that although the glycolipids are recognized by Chagasic patients' sera, the reactive antibodies are not specific since they re acted quite well with murine laminin. Polyspecific antibodies from Cha gasic sera have already been described using other unrelated antigens. (C) 1994 Wiley-Liss, Inc.