Analysis of lipopolysaccharide binding by CD14.

摘要: The cell surface protein CD14 binds bacterial lipopolysaccharide (LPS) in the presence of serum protein, LPS-binding (LBP). This interaction is important for LPS-induced activation mammalian myeloid cells. We performed quantitative studies 3H-labeled LPS binding to human expressed on Chinese hamster ovary cells and a macrophage line (THP-1). At concentrations studied (20-100 nM) required expression could be inhibited by subset anti-CD14 monoclonal antibodies. LBP was CD14. occurred within 10 min relatively unaffected temperature over range 4-37 degrees C. Quantitative assays were at C, or 37 using depleted ATP. In both cases, 75-90% released treatment with phosphatidylinositol-specific phospholipase suggesting that it remains associated glycosyl phosphatidylinositol-anchored apparent dissociation constant recombinant C 2.74 (+/- 0.99) x 10(-8) M; THP-1 4.89 1.42) M. lines, saturating concentrations, molar ratio bound per approximately 20:1. 2.7 1.2) M, 8:1. Although difference two temperatures difficult interpret, clear not 1:1. basis this phenomenon unclear, but may involve repeated leucine-rich motifs, which are found