MATERNAL IMMUNOCOMPETENCE .1. GRAFT VERSUS HOST REACTIVITY OF LYMPHOCYTES FROM PREGNANT RATS AND DISTRIBUTION PATTERN OF CR-51-LABELED LYMPHOCYTES IN PREGNANT MICE

Lymphocytes from the peripheral blood, spleen or para-aortic lymph nodes of primigravida L rats carrying (L .times. BN)F1 (LBN) fetuses are fully capable of mounting graft-vs.-host (GVH) reactions in LBN F1 recipients. The reactivity of lymphocytes from interstrain pregnant (L .times. BN) or intrastrain pregnant (L .times. L) rats, or from rats postpartum from these pregnancies, is equivalent to that of normal virgin females over a full dose-response curve, ruling out specific and nonspecific effects of pregnancy on the intrinsic GVH competence of the maternal thymus-derived (T) lymphocyte. Attempts to block GVH reactivity with serum from pregnant rats were unsuccessful. When the distribution pattern of 51Cr-labeled syngeneic and semiallogeneic lymphocytes was studied in intact primigravida mice, there was no difference between interstrain and intrastrain pregnant mice, and there was no evidence of immunologically specific trapping in the para-aortic lymph nodes draining the interstrain pregnant uterus.