Further studies on the mechanism of pregnancy-induced isoimmunization in mice

Abstract

ABDoM I N AL delivery in mice markedly increases the frequency and intensity of maternal isoimmunization to paternal H-Z antigens. We have previously shown that “uterine spillage” associated with such deliveries is sufficient to explain this immunization response. There also appeared to be a positive correlation between fertility and anti H-Z postpartum titers in this group of mice.3 Because of the analogy between H-2 in mice and Rh in humans (both are erythrocyte antigens determined at a complex genetic locus with a series of cross-reacting alleles and antibodies to both are induced by incompatible pregnancies), study of pregnancy induced H-2 isoimmunization in mice has been continued. Najarian and Dixon7 have noted that maternal administration of hyaluronidase in rabbits doubles the number of maternal red cells that normally cross the placenta. Reported here are further studies of the effects of abdominal delivery on isoimmunization and fertility, of the provocative effect of amniotic fluid injections on H-2 titers of pregnant and nonpregnant females and of hyaluronidase administration effects in pregnancy-induced isoimmunizations. Abdominal delivery. Thirty-six 6-week-old C57B1/6J (H-2b) females were mated to DBA/2J (H-2d) males. Pregnancies were terminated on gestation days 17 and 18 as previously described. Amniotic fluid injections. Amniotic fluid