Alterations in thymus and spleen cell populations and immune reactivity during syngeneic pregnancy and lactation.

Maternal thymus and spleen cell composition and mitogenic responsiveness were examined in the mouse during syngeneic pregnancy and lactation. The results indicated significant changes in thymus cell populations and in thymus cell in vitro mitogen, mixed-leukocyte and in vivo graft-versus-host (GVH) responses during pregnancy and lactation. In the spleen, in vitro mitogen responses were not altered, however, in vivo GVH reactivity was decreased during lactation.