Abstract
It has been suggested that the maternal immune system favors noncytotoxic, “TH‐2” immune responses in order to tolerate the developing fetus. In some strains of mice, pregnant females will reject a male skin graft, even as they tolerate their male fetuses. This rejection is based on responsiveness to the male antigen H‐Y. In this study we test whether functional maternal tolerance of male fetuses is critically dependent on the TH‐2 cytokine Interleukin 10‐(IL‐10). Normal and IL‐10 deficient (10‐KO) females were sensitized against H‐Y by intraperitoneal injection of male spleen cells before mating with 10‐KO males. Litters born to 10‐KO females were of comparable size to those born to normal females of the same genetic background. The proportion of males per litter was not adversely affected by IL‐10 deficiency. Taken together, our work and others suggest that IL‐10 may not be critically important for maternal tolerance of the fetus and extends the evidence against the idea that successful mouse pregnancy depends on TH‐2 deviation of the maternal immune system.