Kinetics of Defense Activities of Inflammatory Neutrophils in Carp and Red Sea Bream.

Abstract

To understand the kinetics of the defense activities of inflammatory neutrophils during inflammation, their chemotactic, phagocytic and respiratory burst activities were examined in inflamed carp (Cyprinus carpio) and red sea bream (Pagrus major) . Formalin-killed Escherichia coli cells were injected into the swim bladder of fish. Inflammatory neutrophils were withdrawn from the swim bladder of the animals at various times (12, 24, 36, 48, 60 and 70 h) after injection. The results obtained for the two species were similar. Neutrophils and macrophages were collected from the swim bladder, while neither lymphocytes nor thrombocytes were found in this region. Neutrophils accounted for the great part of cells exuded into the swim bladder. The number of exudate cells peaked 48 h after injection. The neutrophils isolated at the first sampling time had the highest chemotactic activity. Phagocytic activity of carp neutrophils had the greatest value 48 h after injection, whereas no significant difference in phagocytic activity was observed in red sea bream neutrophils during the experiment. Respiratory burst activities in carp and red sea bream were highest at 48 and 36 h post-injection, respectively. These observations suggest the following course of events : An invasion of irritants induces inflammation. In the early stage of inflammation, the neutrophils with higher migration activity first arrive at the inflammatory site to prevent the spread of irritants. As the inflammation progresses, the neutrophils with higher killing activity follow to eliminate the irritants.