Kinetics of neutrophil accumulation in acute inflammatory lesions induced by chemotaxins and chemotaxinigens

Abstract

The influx of neutrophils into cutaneous lesions induced with the chemotaxins formylmethionyl-leucyl-phenylalanine (FMLP), platelet-activating factor (PAF), and alpha-casein, and the chemotaxinigens endotoxin and zymosan peaked at 2 to 4 hr and then rapidly declined. In contrast, concanavalin A (Con A) induced a biphasic influx of neutrophils with an initial peak at 2 hr and a subsequent, prolonged peak between 6 and 10 hr. When the kinetics of the neutrophil influx into lesions induced with FMLP at 10(-5) M, 10(-6.5) M and 10(-8) M were examined, it was found that a comparable proportion of the total cell influx entered lesions induced with each concentration of FMLP at each time point. This result indicates that the kinetics of the neutrophil influx into an inflammatory lesion is not dependent on the concentration of chemotaxin within the lesion. The inflammatory potency of FMLP, PAF, alpha-casein, Con A, and endotoxin were compared with leukotriene B4 (LTB4) and zymosan-activated plasma (ZAP) as a source of C5 fragments. Equipotent concentrations were 10(-4) M alpha-casein, 10(-5) M PAF, 10(-5.5) M LTB4 and Con A, 10(-6) M FMLP, 10(-7) M ZAP, and 10(-11) M endotoxin.