The Effect of Alpha‐fetoprotein on the Immune Response: Diminution of the Phagocytosis Capacity of Macrophages Cultured <i>in vitro</i> in the Presence of Mouse Amniotic Fluid or Alpha‐fetoprotein

Abstract

A study was carried out on the in vitro phagocytosis capacity of mouse peritoneal macrophages cultured in a medium supplemented with mouse amniotic fluid or alpha‐fetoprotein purified from embryo extract. For this purpose 3 H‐TdR labelled staphylococci and 51 Cr labelled fowl red blood cells were used. Both mouse amniotic fluid and alpha‐fetoprotein inhibited phagocytosis, the antigen being incorporated in smaller amount than in the controls where the medium was supplemented with normal mouse serum. In contrast to fetal glycoprotein, the presence of serum homologous proteins from adult animals did not inhibit the phagocytosis of macrophages but stimulated it. The possible biological implications of this phenomenon are discussed.