Sex Differences in Response to Plasmodium chabaudi Infection: Involvement of Gonadal Steroids

The goal of this study was to examine whether immune responses to Plasmodium chabaudi infection differ between the sexes and are altered by the presence of gonadal steroids. Gonadally-intact males were more likely than intact females to die following P. chabaudi infection, exhibit slower recovery from infection-associated weight loss, hypothermia, and anemia, have reduced IFNγ-associated gene expression and IFNγ production during peak parasitemia, and produce less antibody during the recovery phase of infection. Gonadectomy of male and female mice altered these sex-associated differences, suggesting that sex steroid hormone, in particular androgens and estrogens, may modulate immune responses to infection. Keywords: Time Course Intact and gonadectomized (gdx) male and female C57BL/6 mice were inoculated with 106 P. chabaudi AS-infected erythrocytes and responses to infection were monitored. For microarray analyses, RNA was isolated from 5 x 106 white blood cells (WBCs) that were isolated from spleens 0, 3, 7, or 14 days after inoculation with P. chabaudi. Equivalent aliquots of RNA from 3 animals/treatment group were pooled and 3 separate pools were processed on separate Affymetrix GeneChips (n = 3 GeneChips/time point/treatment group).