Differential production of interferon and lymphotoxin by human tonsil lymphocytes.

Lymphotoxin (LT) production, interferon (IF) production, and DNA synthesis were investigated after mitogen stimulation and in the mixed lymphocyte culture (MLC) reaction using human tonsil lymphocytes. Both LT and IF were assayed in parallel and from the same lymphocyte supernatants. An analysis of the PHA, PWM, one-way and two-way MLC reactions showed that the amounts of LT and IF produced could not be correlated. Polyriboinosinic: polyribocytidylic acid (poly(I: C)) failed to induce either LT production or ³H]TdR incorporation but did induce IF production. Removal of glass-adherent cells (GAC) had no effect on mitogen induced LT production but their removal reduced LT production in MLC reactions. GAC were necessary for IF production and optimal ³H]TdR incorporation in both mitogen stimulated cultures and in MLC reactions. IF and LT activities were shown to be the result of different molecules by using a Sephadex G-75 column. These results indicate that mitogen stimulation differs from MLC reactions in the cell type or control mechanisms involved for LT production, and that in mitogen stimulated cultures all three of these in vitro phenomena are probably the results of either different cell types or of different cell to cell interactions.