The role of suppressor cells in the production of macrophage migration inhibition factor

The production of migration inhibition factor (MIF) by human peripheral blood lymphocytes and guinea pig lymph node lymphocytes, in response to mitogen, concanavalin A, or antigen, tuberculin, has been studied. Suppressor cells have been depleted by in vitro ageing of cultures for 24 hours, and this has resulted in a significant increase in MIF activity. Reconstitution of the aged lymphocyte population by the addition of fresh lymphocytes results in a suppression of MIF production. When lymphocytes, which have been cultured for 24 hours in the presence of antigen or mitogen to generate suppressor cells, are added to aged cultures MIF production is inhibited. These results suggest that suppressor cells play a regulatory role in the production of MIF.