Females in proestrus state maintain splenic immune functions and tolerate sepsis better than males

Objectives: To determine: a) whether the cell-mediated immune response during sepsis differs in females vs, males; and b) whether the survival rate in females is different than in males after a septic insult, Design: A prospective, randomized animal study, Setting: University research laboratory, Subjects: Male and female proestrus C3H/HeN mice, interventions: After anesthesia, male and proestrus female mice underwent cecal ligation puncture to induce sepsis, The mice were killed at 24 hrs after the onset of sepsis, Measurements and Main Results: Splenocyte proliferation, as well as splenocyte interleukin (IL)-2 and IL-3 release, was determined by bioassay, In additional studies, survival rate after septic challenge was measured over 10 days, Splenocyte proliferative capacity and splenocyte IL-2 and IL-3 release were markedly decreased in male, but not in female, septic mice, Furthermore, the survival rate of septic female proestrus mice was significantly higher than in comparable male mice, Conclusions: These results support the concept that the immune response of females differs from males, and that females are immunologically better positioned to meet the challenge of sepsis.