Chemotactic and Leukocytosis-inducing Activities of Eel Complement

Abstract

Biological activities of eel complement activated through the alternative pathway, namely, chemotactic activity and leukocytosis-inducing activity, were investigated.
The normal eel sera were mixed with zymosan or formalin-killed cells of selected bacteria (Escherichia coli, Edwardsiella tarda or Vibrio anguillarum) and incubated at 25°C for 60 min. The sera were separated from zymosan or bacterial cells by centrifugation. And then, this treated sera were heated at 50°C for 30 min.
Chemotactic activity of the treated sera were determined by the modified Boyden chamber method. The distance of eel neutrophil migration toward the treated sera were significantly different from that toward the inactivated sera.
The peripheral neutrophils increased in number rapidly 6-9 hr after the intraperitoneal injection with the treated sera. There appeared to be the leukocytosis-inducing activity in the treated sera.
These biological activites of eel complement indicated in this study may play an important role in the non-specific defence mechanism of eel.