IMMUNOACTIVE PRODUCTS OF HUMAN PLACENTA .4. IMMUNOREGULATORY FACTORS OBTAINED FROM CULTURES OF HUMAN PLACENTA INHIBIT INVIVO LOCAL AND SYSTEMIC ALLOGENEIC AND GRAFT-VERSUS-HOST REACTIONS IN MICE

We have shown in previous reports that human placental supernatants (HPS) display a variety of immunoregulatory properties in vitro. Here we report that these supernatants are able to suppress the ability of murine splenocytes to evoke an allogeneic reaction in the popliteal lymph node (PLN) assay, as well as their capacity to induce both local (popliteal lymph node swelling) as well as systemic chronic or lethal graft-versus-host reactions. Those results are discussed in the light of the potential use of HPS in the control of transplantation immune reactions as well as in the regulation of xenogeneic pregnancies, as the murine system that was used proved that the material exerted an effect across a species barrier.