The CD14 (HI221) antibody recognizes a 53-55 kDa glycosylphosphatidylinositol (GPI)-anchored single chain glycoprotein, which is found on cells of myelomonocytic lineage including monocytes (strongly), granulocytes (weakly) and also on most tissue macrophages. CD14 antigen is also present on reticular dendritic cells, some Langerhans cells, and B lymphocytes (weakly), but is absent from T lymphocytes, NK cells, erythrocytes and platelets. CD14 functions as a high affinity receptor for the comple, Xenopus/Amphibian, of lipopolysaccharide (LPS-endoto, Xenopus/Amphibian,in) and LPS-binding protein (LBP), and is the major receptor involved in the lethal response to both endoto, Xenopus/Amphibian,in and Gram-negative bacteria. In addition to membrane CD14, soluble form of CD14 can be detected in serum and tissue culture supernatants of cells transfected with CD14.