Studies on the production of MIF and mitogenic factor using highly purified human T and B lymphocytes.

Human lymphocytes were separated into highly purified populations using an immunoadsorbent column technique. It was previously reported that both T and B cells exhibited increased 3H-thymidine incorporation in response to PHA, Con A and pokeweed mitogens, whereas only T cells showed increased incorporation in response to specific antigen. In the present studies, the cellular basis of MIF and mitogenic factor production was studied. Both T and B cells produced MIF in response to antigen. The MIF produced by both T and B cells elutes from Sephadex G-100 columns in the same fraction. Studies using BUdR and light suggest that the T cell which produces MIF is also a proliferating cell, whereas the B cell producing MIF is not. Only T cells produce mitogenic factor in response to antigen. The mitogenic factor produced, however, causes both T and B cell populations to increase 3H-thymidine incorporation. The present studies indicate that antigen induced mitogenic factor production and increased 3H-thymidine incorporation are properties of T cells per se, whereas antigen-induced MIF is made by both T and B cells.