[Effect of alpha-mercaptopropionylglycine (alpha-MPG) and sodium dipropylacetate (DPA) on antibody formation (III) (author's transl)].

Mechanisms of the immunostimulative activity. In the present paper, an investigation was carried out to clarify the mechanisms regarding immunostimulative activity of alpha-MPG and DPA. Phagocytosis of peritoneal macrophage was enhanced by high concentration of alpha-MPG, but was unaffected with DPA in vitro. Mice were immunized with an i.v. injection of sheep erythrocytes and 3 days later spleen cells were isolated and incubated with alpha-MPG and DPA FOR 24 HR. Although neither drug affected the number of recovered and living cells, hemolytic plaque forming cells were increased with alpha-MPG and there was a tendency to increase with DPA. Phytohemagglutinin-P and/or lipopolysacchride E. coli-induced blast formation was not reinforced by either drug in spleen cells of mice, and no mitogenic activity was found in the spleen cells. In the early stage of immuno-response to polyvinylpyrrolidone as a T cell independent antigen, the titre of antibody showed no increase after either drug. alpha MPG and DPA apparently act as potentiators in antigen modifications of macrophages.