Down‐modulation of receptors for granulocyte colony‐stimulating factor on human neutrophils by granulocyte‐activating agents

Abstract

Purified human blood neutrophils were able to bind radioiodinated murine granulocyte‐colony‐stimulating factor (G‐CSF) in a specific manner. This factor has previously been shown to stimulate functional activities of human and murine neutrophilic granulocytes and to be functionally analogous to human‐derived CSFβ. The binding of 125I G‐CSF to human neutrophils was competed for equally by unlabeled G‐CSF and CSFβ but not by other CSF's. Saturation analysis indicated that human neutrophils displayed about 700–1,500 receptors for G‐CSF/CSFβ per cell. Three other agents (N‐formyl‐methionine‐leucine phenylalanine, bacterial lipopolysaccharide, and human CSFα) known to activate neutrophils did not..