Active Immunization of Mice with Chagastoxin

Abstract

PREVIOUSLY we reported on the immunology, immunochemistry and immunochemotherapy of experimental Trypanosoma cruzi infection in mice. T. cruzi has at least 9 antigens. Sonic lysates of the cultures contain antigens A, B, C, D, E, F, G and H, and the sediment contains B, E, D and X. Living trypanosomes have antigens B, E and G. Saline supernatant has antigens A, B and F, while distilled water supernatant has A, B and E, and sediment antigens B and X. The recently phenolized cultures have A, B, G and X, and old phenolized cultures have only B. 50 per cent extraction with ammonium sulphate yields A, B, E, G and F. 100 per cent saturation still extracts B, while precipitation with alcohol after full saturation with ammonium sulphate still extracts antigen B. The phenol extract and sediment (Westphal) contain no antigens, but phenol aqueous extract contains antigen B. The antigens B, E and G are major antigens. The agglutinin titre of hyperimmune rabbit serum was 1 : 10,240 and that of horse serum was 1 : 327,600. Both rabbit and horse hyperimmune sera had 1 : 4 titre of agargel precipitin. Immunotherapy with hyperimmune rabbit serum prolonged the survival time in fatal T. cruzi infection in mice two- to three-fold. Chemotherapy with 1-furaltadone, in doses of 50 mg/kg/day for two weeks, followed by 12.5 mg/kg/day for 2.5 months, protected 86.7 per cent of infected mice, while combined immunochemotherapy with hyperimmune rabbit serum plus 1-furaltadone protected all mice for at least 5 months^1–3.