UP-REGULATION OF MOUSE CD14 EXPRESSION IN KUPFFER CELLS BY LIPOPOLYSACCHARIDE

Western blot analysis showed that a monoclonal antibody against recomb inant mouse CD14 (mCD14), designated rmC5-3, specifically reacted with mouse macrophage cell line J774, but not myeloma cell line NS1. Fluor ographic and immunocytochemical analysis demonstrated specific binding of rmC5-3 with mouse resident macrophages, inflammatory monocytes and neutrophils, and macrophage cell lines. Immunohistochemical staining using rmC5-3 showed that CD14-positive Kupffer cells (KC) were small i n number in the liver in nonstimulated mice. The number of stained KC, which were rich in the midzonal and periportal regions, gradually inc reased with time after intraperitoneal injection of lipopolysaccharide (LPS), peaked 6 h after injection, and returned to normal by 20 h aft er injection. Staining intensity over time was proportional to the num ber of KC. A slight increase in mCD14 expression was observed in perit oneal macrophages 2 h after LPS administration in vivo using flow cyto metric analysis. mCD14 mRNA became detectable at 1 h after the intrape ritoneal injection of LPS (20 mu g/mice), and the level dramatically i ncreased with time, peaking at 3 h, and sharply dropped at 6 h. The re sident peritoneal macrophages demonstrated a constitutively high mCD14 mRNA expression, which slightly increased 2 h after LPS (100 ng/ml) s timulation in vitro. The level of mCD14 expression in macrophages did not increase after intraperitoneal injection of LPS (20 mu g/mice).