Possible modulation by male sex hormone of Th1/Th2 function in protection against Plasmodium chabaudi chabaudi AS infection in mice

We examined the mortality, survival time, and parasitemia in interferon gamma receptor (IFN gammaR)-deficient (IFN-gammaR(-/-)) and IL-4-deficient (IL-4(-/-)) mice infected with Plasmodium chabaudi AS and compared them with the wild type counterparts (IFN-gammaR(+/+) and IL-4(+/+), respectively). (1) Mortality was higher and survival time was shorter in males of both IFN-gammaR(-/-) and IL-4(-/-) mice infected with P. chabaudi AS, compared with their wild type counterparts, whereas such a difference was not observed in female mice. (2) These differences between males and females were not observed when male mice were castrated; however, female castration had no effect on the data. (3) The rate of parasitemia in both male and female IFN-gammaR(-/-) and IL-4(-/-) mice was higher at some points during the observation than in the wild type counterparts. (4) These results on susceptibility vs resistance to P. chabaudi AS infection can be explained partially by the levels of expression of Th1/Th2 cytokine and chemokine mRNAs in the spleen cells of the infected mice. These results suggest that male sex hormones modulate the function of Th1/ Th2 cells and that these T cells counteract the activity of these hormones in protection against P, chabaudi AS infection in mice, (C) 2000 Academic Press.