Age and sex differences in the response of lymph node post-capillary venules in mice infected with Toxoplasma gondii.

Groups of male and female mice of varying ages were infected with a low-virulence strain of Toxoplasma gondii and killed 3 weeks and 6 weeks after infection. The lymph nodes of the female group showed a greater prominence of the endothelial cells of the post-capillary venules. This difference was most marked at the age of 15 weeks and least at 30 or more weeks. The same sex difference was demonstrated in control mice although to a lesser extent. The possible role is discussed of the effect of female sex hormones on vascular endothelium in modifying the development of an immune response and in explaining the observed female preponderance in human cases of auto-immune disease.