Fig. 8. Chagasin and cruzipain bind to the cell surface of T. cruzi amastigotes and trypomastigotes. Living parasites were washed twice in PBS, 2 mM EDTA, incubated in the same buffer containing FITC-chagasin or FITC-cruzipain, for 30 minutes at 4°C, washed and fixed with 3% paraformaldehyde. Upper panels are phase-contrast and the lower ones are fluorescence microscopy. (A,B) Cell surface binding of FITC-chagasin (E,F) Cell surface binding of FITC-chagasin preincubated with unlabeled n-cruzipain. (C,D) Cell surface binding of FITC-cruzipain.