Cellular immune aspects of the human fetal-maternal relationship.

In the present study the number and the function of T lymphocytes obtained from peripheral blood of 35 mothers immediately after delivery and from the cord blood of the respective newborns were tested. Furthermore, the effect of the newborns' lymphocytes on the immunological competence of the mothers' lymphocytes was investigated by means of graft-versus-host-reaction xenograft test. The blood of 14 of the mothers and their newborns was also examined by monoclonal antibodies for determination of T helper and T suppressor lymphocytes. A marked reduction in the absolute number of T helper cells was found in the blood of mothers after delivery. In addition, mothers' lymphocytes manifested a high suppressor activity when added to normal human lymphocytes. It was also found that the cord blood contains lower number and percentage of T suppressor cells. Yet the T cells of the cord blood exert a high suppressor activity on the mother as well as on normal donor lymphocytes. The impaired function of cord blood lymphocytes could be impaired function of cord blood lymphocytes could be restored by in vitro addition of THF, a thymic hormone.