Amphibian lymphokines: 2 Migration inhibition factor produced by antigenic and mitogenic stimulation of amphibian leucocytes

Migration of Rana temporaria peritoneal exudate cells (PEC) was examined in vitro using both direct and indirect assay systems. After sensitization in vivo followed by in vitro challenge 7–21 days later with the appropriate sensitizing antigen, spleen cell culture supernatants were obtained which inhibited the normal in vitro migration of PEC from non-sensitized animals. Cultures of spleen cells with mitogen also gave rise to supernatants with migration inhibitory properties. Sephadex separation of supernatants showed that maximum inhibitory activity was present in the 27–50,000 MW range and, furthermore, that this inhibition was blocked by α-L-fucose, but not by B-D-galactose. The inhibition did not appear to be species specific. The results indicate that following appropriate stimulation amphibian leucocytes produce a soluble, migration inhibition factor (MIF) with characteristics similar to those described for the mammalian lymphokine MIF.