Innate immunity to Toxoplasma gondii is influenced by gender and is associated with differences in interleukin-12 and gamma interferon production.

Given that differences between the sexes in relative susceptibility to parasitic infections have been noted, this study further elucidates the mechanisms responsible by demonstrating that male SCID mice are more resistant than female mice to infection with Toxoplasma gondii and that this difference correlates with enhanced innate immune responses in these animals. Male SCID mice exhibited longer survival times, lower parasite burdens, and less severe pathological changes postinfection. An immunological basis for these differences is demonstrated in that these animals produced interleukin-12 more rapidly and exhibited higher levels of gamma interferon earlier postinfection.