Differences in the expression of Ly-6C on neutrophils and monocytes following PI-PLC hydrolysis and cellular activation.
All leukocytes, except some subsets of lymphocytes, express Ly-6C. However, virtually all of the regulation studies of this antigen have been done on lymphocytes only. Recently we showed that monocytes and neutrophils express 10-100 times the level of Ly-6C expressed by lymphoid cells. We compared Ly-6C expression on neutrophils and monocytes following short-term cell activation induced by C5a or phorbol esters or treatment with phosphatidylinositol-specific phospholipase-C (PI-PLC). Activation of the neutrophil led to a rapid ( < 30 min) increase in surface expression of Ly-6C, but similar treatment had little effect on or slightly diminished the expression of the monocyte molecule. Prolonged treatment of the monocyte with IFN-gamma (24 h) led to increased Ly-6C expression. Low doses of TNF-alpha inhibited the up-regulation of Ly-6C induced by IFN-gamma. Similar to what has been described for the lymphocyte, the monocyte form of Ly-6C was hydrolyzed by PI-PLC treatment within 30 min. In contrast, the neutrophil molecule was unaffected by PI-PLC for up to 2 h. SDS-PAGE Western blot analysis demonstrated that the neutrophil and monocyte molecules were in the same molecular weight range (14-18 kDa Mr). Our results clearly show differences in the regulation of Ly-6C expression on monocytes versus neutrophils. Thus, it is likely that the potential function of Ly-6C will be unique for each cell.
Montana State University, Bozeman 59717.
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Jutila
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Kurk
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Jutila
D000818:Animals; D000950:Antigens, Ly / Q000378:metabolism*; D015936:Complement C5a / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006868:Hydrolysis; D007371:Interferon-gamma / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000378:metabolism*; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D054801:Phosphoinositide Phospholipase C; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D011994:Recombinant Proteins; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation
D000950:Antigens, Ly; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D015936:Complement C5a; D007371:Interferon-gamma; D010727:Phosphoric Diester Hydrolases; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D013755:Tetradecanoylphorbol Acetate