[Action of isoprinosine on the "in vitro" activation of human lymphocytes (author's transl)].

The action of isoprinosine on lymphocytes stimulated by optimal or suboptimal concentrations of polyclonal mitogens (ConA and PWM) was studied in 3, 5 and 7-days cultures. In some experiments, varying concentrations of isoprinosine were added to lymphocyte cultures at variuos times. Isoprinosine exerted no effect on non stimulated cells but enhanced the proliferative response in the presence of mitogens. The optimal response was obtained with a dose of 1 000 micrograms (/10(6) cells) of isoprinosine and on the 5th day in the cultures stimulated by ConA or PWM, but an enhancing effect could still be detected on the 7th day of culture. The effect seems stronger when isoprinosine is introduced earlier in the course of the cultures. Preliminary experiments suggest that isoprinosine increase the proliferation of both T and B cells and that its activity on B cells could be due to the potentiating action of helper T cells.