Some properties of the mitogenic factor induced in human lymphocytes under the influence of phytohemagglutinin]

Production of the PHA-induced human lymphocyte mitogenic factor (MF) previously described by the author and its influence on the lymphoid cells were investigated. The PHA-antiserum and immunosorbents were used for the PHA inactivation. The PHA-stimulated lymphocytes produced the mitogenic factor (MF) during the G1 period and the beginning of the S period of the cell cycle. When the cells were cultivated in the protein-free medium, the level of the DNA and the protein synthesis was significantly decreased, but the level of the MF production was 1.6 times greater than that of the MF production in the protein-containing medium. Kinetics of the lymphocyte reaction to the MF is described: DNA synthesis (as judged by the H3-thymidine uptake) began on the 5th--6th day and reached the maximum on the 6th--7th day.