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 degrees C to 34 degrees C. Challenge of mice with blood-form trypomastigotes produced high parasitemias when animals were immunized with surface proteins from epimastigotes cultured at 30 degrees C and with Nonidet P-40-extracted epimastigotes pellets cultured at 34 degrees C. However, low parasitemias were recorded after immunization with surface proteins from epimastigotes cultured at 34 degrees C or Nonidet P-40-extracted epimastigotes pellets at 30 degrees 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 degrees C and treated with tosyl-L-lysine-chloromethyl ketone.