THE N-FORMYL METHIONYL PEPTIDE, FORMYL-METHIONYL-LEUCYL PHENYLALANINE (FMLF) INCREASES THE LATERAL DIFFUSION OF COMPLEMENT RECEPTOR 1 (CR1/CD35) IN HUMAN NEUTROPHILS - A CAUSATIVE ROLE FOR OXIDATIVE METABOLITES

摘要

The effects of the N-formyl methionyl peptide, formyl-methionyl-leucyl phenylalanine (fMLF) on the lateral mobility of the complement receptor type 1 (CR1/CD35) in glass-adherent human neutrophils were investigated, using fluorescence recovery after photobleaching (FRAP) and confocal microscopy (CSLM). It was found that addition of 0.1-1 mu M fMLF increased the diffusion constant (D) of CR1/CD35 to 167-278% of controls. No effect was observed on the receptor distribution or the mobile fraction of receptors. The effect of fMLF on the lateral diffusion of CR1/CD35 could be totally inhibited by addition of pertussis toxin (PT,250 ng/ml) or of the free radical scavenger enzymes superoxide dismutase (SOD, 2000 U/ml) and catalase (CAT, 200 U/ml), added together the results show that oxidative metabolites produced by neutrophils in response to fMLF can modulate CR1/CD35 diffusion, and indicate a regulatory role for oxygen radicals in phagocytosis. [References: 44]