IMMUNE REACTIONS OF NORMAL PREGNANCY

Eight hundred and twenty-four serial blood sera were obtained from 66 clinically normal pregnant patients. The sera were applied to sections of the placenta from the corresponding pregnancy and stained with fluorescein-tagged goat anti-human globulin. By this immunofluorescence technique, globulin binding was demonstrated in the first trimester sera of the large majority of the cases studied and in one third of the postpartum specimens. The sera demonstrating the strongest response were then subjected to a panel of fluorescein-tagged goat antibodies to specific human protein fractions. This revealed the maternal serum component to be in the gamma G fractions. Prior treatment with goat anti-human immunoglobulins inhibited the reaction. These findings correlated well in time and frequency with the transplant rejection reaction in the decidua previously reported by the authors. The possible etiology of the decline in the immune response is discussed. © 1969.