Studies on non-specific defence mechanism to bacterial infections in fishes.

点击翻译按钮获取中文摘要

Biological activities of eel complement activated through the alternative pathway were investigated. The normal eel sera were mixed with zymozan, which is known as an activator for the pathway, or formarin-killed cells of selected bacteria and incubated at 25 C for 60 min. The sera were separated from zymosan or the bacterial cells by centrifugation. First, chemotactic activity of the treated sera were determined by a modified Boyden chamber method. The distance of eel neutrophil migration toward the treated sera were significantly different from that toward the heat-inactivated sera. Secondly, leukocytosis-inducing activity was exzamined by intraperitoneally injecting eel with the treated sera. A rapid increase in the number of peripheral neutrophils was observed in the eel and reached a peak 6 - 9 hour after injection. In addition to bactericidal activity demonstrated in our earlier work these chemotactic and leukocytosis-inducing activities of eel complement appeared important in th … More e non-specific defence against bacterial infections.Neutrophils were seperated from the peripheral blood of eel. One ml of undiluted blood were carefully loaded onto a discontinuous density Ficoll-metrizoate ( 1.073, 1.083 and 1.089 in density) solution and the tube was centrifuged for 30 min at 1500 rpm. A fraction containing heavier neutrophils was obtained from the blood of eel injected with bacterial dead cells one day befor blood collection. The 'heavy' neutrophils were not obtained from eel injected with the treated sere, casein or saline (control). They were more active in phagacytosis than the ordinal 'light'ones.Phagocytosis of eel neutrophils isolated from peripheral blood was measured by chemiluminescence (CL) assay. When neutrophils were exposed opsonized bacteria, CL respones increased rapidly. CL response to the non-opsonized bacteria was much lower than that to the opsonized ones. The amount of CL respones became larger in proportion to the concentration of normal serum as an opsonin. CL response in phagocytosis of carp neutrophils was similar to that of eel in pattern, but much lower in intensity. It was found that the CL assay could be applied not only to investigate the magnitude and kinetics of phagaocyte but also to assess the serum opsonic activity. Less