Soluble factors in tolerance and contact sensitivity to 2,4-dinitrofluorobenzene in mice. IV. Characterization of migration inhibition factor-producing lymphocytes and genetic requirements for activation.

The production of migration inhibition factor (MIF) in vitro by lymph node cells from mice with contact sensitivity to 2,4-dinitrofluorobenzene (DNFB) was investigated. MIF activity of cell-free culture supernatants was measured using a micro, indirect "hanging-drop" assay system. We found that DNFB-sensitized lymph node cells are stimulated to produce MIF by co-culture with DNP-labeled spleen cells or splenic adherent cells. The stimulation was quantitatively antigen-specific, as co-culture with TNP-spleen cells or TNP-splenic adherent cells induced only low levels of MIF activity. Pretreating the immune lymph node cells with different antisera plus complement, before addition of DNP-spleen cells, showed that MIF production is dependent on Ia- T cells. Additional experiments showed that in order for the T cells to be stimulated, homology at the I-A subregion of the major histocompatibility complex between the T cells and DNP-spleen cells is required. Collectively, these results correlate with our previous finding that transfer of contact sensitivity is mediated by Ia- T cells and indicate that both tests, i.e., transfer in vivo and MIF production in vitro, are measuring effector functions of the same T cell subset.