IDENTIFICATION OF AN IMMUNOSUPPRESSIVE FACTOR IN PREGNANCY SERUM

  • 1 January 1976
    • journal article
    • research article
    • Vol. 48  (3) , 305-311
Abstract
Complement-inactivated allogeneic serum contained a factor capable of suppressing BCG-induced inhibition of leukocyte migration in vitro. Although serum from late pregnancy was the most potent in this context, the ability to antagonize the leukocyte response appears to be an intrinsic property of human serum. The inhibitory factor was purified by salt fractionation and gel chromatography, and the effect was associated with .alpha.-globulins of high lipid content which are probably .alpha.-lipoproteins. Estrogens, progesterone or corticosteroids, associated with the lipoprotein, did not appear to be the cause of the observed suppression. The factor appears to block the immune response at the level of the lymphocyte, and its nonspecific immunosuppressive properties could contribute to acceptance of the fetus by the mother.