Membrane expression of Fc-receptors in cultured leukemic cell lines. I. Induction of Fc-receptor in undifferentiated types of cells after passive modulation of lipid viscosity
Kyoizumi, S.; Kannagi, R.; Masuda, T.
Journal of Immunology 127(6): 2252-2256
1981
ISSN/ISBN: 0022-1767 PMID: 7299128 Document Number: 168540
The role of the lipid environment of the plasma membrane for the expression of IgG Fc receptor (FcR.gamma.) was studied by physicochemical modifications of the membranes of mouse myeloid leukemia cell line cells, M1. Sterol binding polyene antibiotics such as amphotericin B or filipin inhibit the expression of FcR.gamma. during the induction of differentiation of M1- cells by conditioned medium obtained from the culture of mouse embryonic fibroblasts, suggesting the possible involvement of cholesterol molecules in the induction mechanism. Low-temperature incubation at 20 or 4.degree. C increases membrane microviscosity as tested by the fluorescence depolarization method, which is accompanied by the appearance of FcR.gamma. on .apprx. 60% of M1 cells as assayed by the erythrocyte-antibody(EA)-rosetting method. FcR.gamma. are also induced on .apprx. 40% of M1- cells by incubating cells with cholesterol-phosphatidylcholine liposomes, which concomitantly increases their membrane microviscosity. No phagocytosis of EA is observed in cells treated with such physicochemical procedures. FcR.gamma. apparently are embedded in the membranes of M1- cells and physicochemical modification of the membrane lipid bilayers may induce FcR.gamma. independently of their functional differentiation (expression of phagocytic activity).