The effects of phytohemagglutinin on the growth and histochemical properties of mammalian cells in tissue culture.

Abstract

AbstractPhytohemagglutinin‐P (PHA‐P) exhibited inhibitory action on the growth of two human epithelioid cell lines, HeLa and L‐132, and on the L‐929 strain of mouse fibroblasts. Growth of stationary cultures was measured spectrophotometrically by DNA production after 96 hours incubation. The mitotic indices of the three cell lines were reduced significantly by PHA‐P after 72 hours incubation.Histochemical studies demonstrate depressed production of cytoplasmic RNA in 72‐hour HeLa cultures after treatment with PHA‐P, with the appearance of prominent, PAS‐positive, diastase‐fast granules in the cytoplasm. Bound lipid aggregates increased in amount in the cytoplasm of HeLa cells after PHA‐P treatment. The PAS‐positive, diastase‐fast granules were also found in the cytoplasm of the L‐132 and L‐929 cell lines after treatment, but cytoplasmic RNA remained unchanged qualitatively. Alkaline phosphatase was slight in amount in HeLa cells and was reduced to trace amounts after PHA‐P treatment. L‐132 cells showed moderate to heavy concentration of alkaline phosphatase, which remained unchanged qualitatively after PHA‐P treatment. The enzyme could not be demonstrated in the L‐929 fibroblasts.