[Effect of inhibitors of DNA and protein synthesis on production of mitogenic factor by human lymphocytes stimulated with phytohemagglutinin].

A study was made of the influence of DNA and protein synthesis inhibitors on the production of mitogenic factor (MF) by human lymphocytes stimulated with phytohemagglutinin. Inhibition of the DNA synthesis with mitomycin failed to decrease MF production but in inhibiting the protein synthesis MF factor production was even increased. A conclusion was drawn that MF preexisted in the lymphoid cell before the beginning of stimulation, not in the ready from but as an inactive precursor; it became activated only in the living cells stimulated with phytohemagglutinin no protein synthesis is required at that moment.