Chemotactic factor inactivator release from rat leukocytes.

Rat neutrophils, alveolar macrophages, and peritoneal macrophages each released chemotactic factor inactivator (CFI) activities under conditions of endocytosis (uptake of opsonized zymosan particles and preformed immune complexes). CFI activities in supernatant fluids from phagocytizing leukocytes were found for the chemotactic factors from the third (C3) and the fifth (C5) components of complement and for the bacterial chemotactic factor (present in culture supernatant fluids from Escherichia coli.) CFI activity could also be demonstrated in homogenates obtained from disrupted leukocytes. CFI release from intact leukocytes was dependent on the duration of incubation of leukocytes with the phagocytic stimulus. No quantitative relationships were noted between the amount of CFI activity and the amount of beta-glucuronidase in phagocytic supernatant fluids released from leukocytes. The release of CFI activities from phagocytizing leukocytes may represent a regulatory ("turn-off") mechanism for the inflammatory response.