Characterization of C1 inhibitor binding to neutrophils.

摘要: In a previous study we have isolated neutrophil membrane proteins that non-covalently bind to native C1-INH (105,000 MW) and non-functional, degraded (88,000 MW; C1-INH-88). To further characterize the binding nature, designed novel kinetic C1 titration assay which enables not only quantification of removal fluid-phase by neutrophils, but also concomitant measure residual function. Native C1-INH, when adsorbed EDTA-pretreated lost its function in inhibition C1. The non-functional C1-INH-88, is probably devoid reactive centre, was found block neutrophils. Pretreatment neutrophils with serine esterase inhibitors did abrogate capacity cells for whereas affinity were pretreated trypsin. An array human peripheral blood leucocytes several lymphoid cell lines has surface sites on erythrocytes U937 cells. Binding confirmed using (i) C1-INH-microsphere beads blocked pretreating excess or trypsin, (ii) radiolabelled competitively unlabelled C1-INH-88. Desialylation significantly reduced indicating receptor could be specific sialic acid residues C1-INH. Overall, our studies indicate other possess acid-containing portion