Studies on the 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 choleraneuraminidase. T and B lymphocyte populations were separated and the effect of these enzymes plus phytohaemagglutin or Tuberculin was studied. The results of these experiments show that proteases moderately stimulate spontaneous deoxynucleic acid synthesis of control cells and potentiate the effect of tuberculin on sensitized cells. These enzymes act specifically on B lymphocytes. Neuraminidase also increases spontaneous deoxyribonucleic acid synthesis of control cells and augments significantly the in vitro response to PPD. There is no additive effect of neuraminidase on phytohaemagglutin stimulated cells. Neuraminidase seems to stimulate specifically T lymphocytes. Some possible mechanisms of action of these enzymes are proposed and discussed.