[Characteristics of T-cells synthesizing macrophage migration inhibition factor in an H-2 system]

Migration inhibition factor (MIF) was found to be produced by T-cells rather than B-cells as shown by the indirect macrophage migration inhibition test in the H-2 system performed with fractionated lymphocytes. MIF-producers appeared to be more sensitive than T-killer cells to the cytotoxic action of anti-theta-antibodies, plus complement. MIF synthesis by lymph node cells developed earlier after immunization than the cytotoxic activity of these cells. These findings indicated that T-cell subpopulation producing MIF differed from the cytotoxic T-lymphocytes.