THE IN VITRO DIFFERENTIATION OF MONONUCLEAR PHAGOCYTES. I. THE INFLUENCE OF INHIBITORS AND THE RESULTS OF AUTORADIOGRAPHY.

The influence of selected inhibitors of protein synthesis on the in vitro differentiation of mouse mononuclear phagocytes has been investigated. DL-p-Fluorophenylalanine at concentrations of 250 microg/ml inhibits the formation of three lysosomal hydrolases, cytochemically demonstrable acid phosphatase and osmiophilic, phase-dense granules. These effects occur in the absence of cell death and are reversed by L-phenylalanine. Puromycin at concentrations of 0.2 to 0.4 microg/ml has a similar effect on both the morphology and biochemistry of cell maturation. Colchicine at a concentration of 0.05 microg/ml inhibits the growth in cell diameter and has less of an effect on enzyme production. Cells exposed to leucine-H(3) for 2 to 3 minutes exhibit the localization of grains in the perinuclear-dense granule region. After an exposure of 60 minutes a similar localization is evident but with a correspondingly greater number of grains. A similar localization of grains occurs when choline-methyl-H(3) is employed as a tracer. The data suggest the storage of newly formed protein and possibly phospholipid in the centrosphere region.