Migration Inhibitory Effect of Cell-Free Supernatants from Mixed Human Lymphocyte Cultures

Cell-free supernatants from mixed human lymphocyte cultures inhibited the migration of non-separated human peripheral leucocytes and purified polymorphonuclear leucocytes. The maximum inhibitory effect was observed in 4-day cultures, but even after 2 days inhibitory effect was demonstrated. The migration inhibitory factor (MIF) from mixed lymphocyte cultures was non-dialyzable, 56°C heat-stable and non-sedimentable at 78,000 × G. MIF was produced also in mixed cultures of lymphocytes pretreated with mitomycin C although the inhibitory effect was diminished in most of these experiments. The migration inhibition was demonstrated with an agarose plate technique which permits examination of only a few hundred microliters of unconcentrated MIF-containing supernatant.