RESUMO
Highly susceptible C3HeB/FeJ mice survive an otherwise lethal infection with a Brazil strain of Trypanosoma cruzi when held at an elevated environmental temperature of 36 C. The body temperature of these mice has been shown to increase 3-4 C to levels typical of a febrile response. In the present study, the synthesis of parasite heat shock proteins (hsp60, hsp70, and hsp90) was shown to be enhanced at a temperature of 39 C and the results of immunoprecipitation analysis indicated that parasite HSPs are highly immunogenic in T. cruzi-infected mice maintained at 36 C or room temperature (RT). Differences in the histopathology of cardiac and skeletal muscle in C3HeB/FeJ mice maintained at RT or 36 C at different times postinfection also were investigated in this study. The lower numbers of circulating parasites observed in mice maintained at 36 C were correlated with lower levels of tissue parasitism, inflammation, and tissue destruction. Finally, the transfer of infected mice from RT to an environment of 36 C at various times during infection was shown to increase the survival rate of infected mice and also resulted in a dramatic reduction in parasitemia levels. In light of the growing evidence for a beneficial effect of elevated temperature during experimental Chagas' disease, further studies seem warranted to determine if hyperthermia or fever therapy might also be beneficial in the treatment of humans infected with T. cruzi.
