Effects of isoprinosine, levamisole, muramyl dipeptide, and SM1213 on lymphocyte and macrophage function in vitro

Four immunopotentiators, levamisole, isoprinosine, muramyl dipeptide, and SM1213, were analyzed in vitro for their effect on phytohemagglutinin-induced lymphocyte proliferation and lymphokine-induced macrophage proliferation and activation to kill Listeria monocytogenes. Isoprinosine augmented all three functions. Levamisole augmented lymphocyte proliferation and lymphokine-induced macrophage activation. Muramyl dipeptide and SM1213 induced macrophage activation directly. The effects of these agents on these cells at concentrations relevant to in vivo therapy support their immunopharmacologic application to modify cellular immunity.