A neutrophil chemotactic factor and its inhibitor found in DNCB-induced skin inflammatory lesions

Neutrophil chemotactic factor(s) and their inhibitors were explored in the acute inflammatory skin lesions induced by the application of 4% DNCB solution with acetone in guinea pigs. Skin biopsies were taken periodically and tissue extracts were made from the biopsy specimens. Neutrophil chemotactic activity found in such extracts reached a peak at 12 to 24 hr after the induction of the inflammation, when the lesions were found to be infiltrated predominantly with neutrophils. After 24 hr, the activity gradually diminished. Physicochemical and antigenic characterization studies on the chemotactic substance indicated that the material was most likely the cleavage product of C3. On the other hand, inhibitors against the neutrophil chemotactic factor were found in the tissue extracts which were obtained from the lesions at a later stage (48 to 96 hr after the induction of the inflammatory reaction). These inhibitors blocked not only the complement-derived chemotactic activity but also that obtained from bacterial culture filtrates. They were heat labile and showed striking heterogeneity in size on Sephadex gel filtration.