Publication Date


Degree Program

Department of Biology

Degree Type

Master of Science


Several investigators have demonstrated an increased resistance to the protozoal parasite Trypanosoma cruzi (the causative agent of Chagas' disease) in highly susceptible C3H mice when maintained at an environmental temperature of 36°C. This increased resistance is manifested as delay in onset of parasitemia, decreased parasitemia, decreased pathology, and increased longevity with eventual clearing of the parasite from the bloodstream. In addition, this enhanced resistance has been shown to be an immunologic phenomenon and not due to the direct effects of elevated temperature on the parasite itself. To ascertain the possible contributions of humoral vs. cellular immunity to the above phenomenon, the relative success of passive transfer of sera and adoptive transfer of whole spleen cells was evaluated. Parasitemias and mortality of donor mice maintained at 21°C or 36°C were monitored. The same parameters were monitored in infected recipient mice held at 21°C and either given sera or whole spleen cells, from the donors, in an attempt to transfer protective immunity. The results of this experiment indicate that 1) an environmental temperature of 36°C does reduce the course of infection with T. cruzi, 2) the positive effects of elevated temperature can be transferred to naive mice through the administration of whole spleen cells from surviving mice, 3) the beneficial effects are magnified as demonstrated by negligible parasitemias and more rapid clearing of blood-form trypomastigotes in the recipients of whole spleen cells as compared with the original mice that survived infection at 36°C, and 4) the positive effects cannot be attributed to antibodies due to the failure of passive transfer to impart any protection beyond that noted in the controls.


Medical Sciences