Selective enhancement of the expression of granulocyte functional antigens 1 and 2 on human neutrophils.

The regulation of expression of two human granulocyte functional antigens (GFA-1 and GFA-2) was examined. N-formylmethionylleucylphenylalanine (fMet-Leu-Phe) caused a rapid, dose-dependent enhancement of the expression of these antigens, 2- to 4-fold within 30 min, but not of another surface structure, beta 2-microglobulin. Pretreatment of the cells with cytochalasin B at 5 micrograms/ml further enhanced the effect of fMet-Leu-Phe on the expression of GFA-2, raising its surface expression 11-fold. Lipopolysaccharide also stimulated the expression of GFA-1 and GFA-2. The effect of lipopolysaccharide was less than that of fMet-Leu-Phe and was more marked on GFA-1 than on GFA-2. Pretreatment of neutrophils with fMet-Leu-Phe not only stimulated their cytotoxic activity against antibody-coated target cells but also increased their capacity to be stimulated by monoclonal antibodies to GFA-1 and GFA-2. These findings show that the expression of functional surface structures on human neutrophils is subject to rapid and selective regulation.