Lymphotoxin and chemotactic factor produced in vitro by human lymphocytes during their proliferative response in the presence of phytohaemagglutinin and Nocardia water-soluble mitogen.

The present investigation was initiated for the purpose of elucidating which cell type, T and/or B lymphocytes, were responsible for human lymphotoxin (LT) and human chemotactic factor (CF) production in vitro. T- and B-enriched subpopulations were tested for proliferative responses and lymphokine release in the presence of a human T mitogen, phytohaemagglutinin (PHA), and a human B-mitogen, Nocardia water-soluble mitogen (NWSM). We found that PHA-stimulated T cells produced LT and CF whereas NWSM-stimulated B-enriched subpopulation released LT and CF.