Suppression of B cell MIF production by T cells and soluble T cell-derived factors.

Purified populations of guinea pig B cells from nonimmunized animals may be stimualted by PPD or LPS to produce MIF. Unfractionated lymphocyte suspensions from these animals do not produce MIF under these conditions. Reconstitution of B cells with T cells abolishes their ability to generate detectable MIF. A soluble factor obtained from stimulated T cell cultures (MIFIF) is also capable of suppressing this B cell activity. Thus suppressor T cells can interfere with lymphokine production by B cells and this effect is mediated at least in part by a soluble factor. This previously undescribed capacity of T cells may provide an explanation for the fact that B cells do not appear to play a role in reactions of cell-mediated immunity in vivo.