STUDIES ON MITOGENIC ACTIVITY OF TRYPSIN, PRONASE AND NEURAMINIDASE ON HUMAN PERIPHERAL-BLOOD LYMPHOCYTES

Human peripheral blood lymphocytes were cultured in the presence of protease (trypsin and pronase) and Vibrio cholerae neuraminidase. T [thymus-derived] and B [bone marrow-derived] lymphocyte populations were separated, and the effect of these enzymes plus phytohemagglutin or tuberculin was studied. Proteases moderately stimulate spontaneous DNA synthesis of control cells and potentiate the effect of tuberculin on sensitized cells. These enzymes act specifically on B lymphocytes. Neuraminidase also increases spontaneous DNA synthesis of control cells and significantly augments the in vitro response to PPD [purified protein derivative]. There is no additive effect of neuraminidase on phytohemagglutin stimulated cells. Neuraminidase seems to specifically stimulate T lymphocytes. Some possible mechanisms of action of these enzymes are proposed and discussed.