Immunomodulatory effects of arginine butyrate.

We have studied the effect of arginine butyrate on T cell and macrophage functions. When target cells are treated with this substance, they become resistant to T cell-mediated cytotoxicity, as detected by the chromium assay. In contrast, when effector T cells are treated, the cytotoxicity seems to be augmented. Peritoneal macrophages incubated with butyrate are increasingly adhesive to substrate. After in vivo treatment, spleen derived macrophages show an augmented cytostatic capacity in the presence of L1210 cells and an enhanced phagocytic activity for IgG-coated erythrocytes. To sum up, the overall effects of butyrate salts on different immune functions are somewhat reminiscent of that of interferon. It is likely that these immune effects contribute, at least in part, to explain its antitumor properties observed in grafted tumors in mice.