VARIABILITY OF TRYPANOSOMA-CRUZI EPIMASTIGOTE SURFACE-ANTIGENS WITH CHANGES IN THE TEMPERATURE OF THE CULTURES

Trypanosoma cruzi epimastigotes changed their pattern of surface proteins when the temperature of growth rose from 30°C to 34°C. Challenge of mice with blood-form trypomastigotes produced high parasitemias when animals were immunized with surface proteins from epimastigotes cultured at 30°C and with Nonidet P-40-extracted epimastigotes pellets cultured at 34°C. However, low parasitemias were recorded after immunization with surface proteins from epimastigotes cultured at 34°C or Nonidet P-40-extracted epimastigotes pellets at 30°C. The lowest parasitemia, together with the longest survival time and absence of immunosuppression, was observed after immunization of mice with the product extracted with non-ionic detergent from epimastigotes grown at 30°C and treated with tosyl-L-lysine-chloromethyl ketone.