THE IMMUNODEPRESSIVE EFFECT OF HUMAN GLUCOPROTEINS AND THEIR POSSIBLE ROLE IN THE NONREJECTION PROCESS DURING PREGNANCY

Abstract

Human chorionic gonadotrophin (HCG) and human chorionic somatomammotrophin (HCS) were shown to suppress the proliferative T and B cell response induced by different mitogens in human and mouse lymphocytes. Thyroid stimulating hormone (TSH), sharing the alphachain subunit with HCG was devoid of effect suggesting that the immunosuppressive entity is localized within the beta‐chain subunit. Human growth hormone (HGH) which is partly biologically cross‐reactive with HCS did not impair mitogen responsiveness.HCG was also able to inhibit the differentiation of cells since the induction of antibody‐formation was depressed. Expression of plaque forming cells was also reduced by addition of HCG directly in the PFC assay possibly reflecting the anti‐complementary effect of this hormone, since cell mediated lysis of target cells by Con A activated lymphocytes, which is not complement‐dependent, was unaffected by adding HCG in the assay system.