The monoclonal antibody 18D11 recognizes human monocyte marker CD14, a 53 kDa glycoprotein. CD14 is a glycophosphatidylinositol-linked protein, which is part of the LPS receptor complex. CD14 binds lipopolysaccharide (LPS) and as such, acts as a pattern recognition receptor (PRR). CD14 has also been suggested to mediate phagocytosis of bacteria an apoptotic cells. CD14 is involved in the endotoxin mediated release of Tumor Necrosis Factor-alpha by monocytic cells. CD14 is present on most monocytic and macrophage like cell types: monocytes, macrophages, Kupffer cells, pleural phagocytic cells and dendritic reticular cells. CD14 is present at low density on a subpopulation granulocytes and activated or transformed B-cells.The monoclonal antibody 18D11 reacts with both soluble and membrane CD14. The monoclonal antibody 18D11 is useful for inhibition of biological activity of sCD14, it inhibits LPS induced TNF production.The monoclonal antibody is cross reactive with pig CD14. Together with a C5a neutralizing monoclonal antibody, 18D11 blocks sepsis in a pig model.