Kinetics of development of the inhibitory activity of mixed lymphocyte culture supernatants on macrophage migration: effect of presensitization

Supernatants of mixed cultures of Lewis and August rat lymphocytes show a spontaneous release of MIF-like activity beginning at the 20th hr of the culture. If the Lewis rat has received an August skin allograft 2 wk earlier, the release begins sooner and remains stronger throughout the 3 days of the mixed lymphocyte culture. The difference begins to be statistically significant at the 10th hr (p < 0.001) and is still highly significant with the 72-hr supernatant (p < 0.001). Such a comparison of the kinetics of MIF-like activity release in mixed lymphocytes cultures between donor-recipient pairs and similar nongrafted pairs may be of both practical and theoretical interest.