IMMUNOSUPPRESSIVE ACTION OF PHYTOHEMAGGLUTININ - EFFECT ON PERITONEAL MACROPHAGES

It has been demonstrated that the immunocompetence of mouse peritoneal cells was not affected by treatment with PHA as measured by their ability, after in vivo erythrophago-cytosis, to elicit antibody synthesis in syngeneic recipients. However, synthesis of antibody was impaired in recipient mice treated with PHA intraperitoneally prior to receiving the antigen-containing cells by the same route. Inhibition of antibody production was not observed when recipients were treated with PHA absorbed with sheep red cells or when transfer of the antigen-containing peritoneal cells were carried out by the intravenous route. The amount of cell-associated radioactivity retained in the peritoneal cavities of PHA-treated mice 2 h after an intraperitoneal injection of 32P-labeled macrophages was twofold greater than that in the saline control mice. The mechanism of action of PHA on humoral antibody production is discussed. © 1969 S. Karger AG, Basel.