抄録
It is well known that fish serum posesses two pathways of complement activity homo-logous to mammalian complement. One is called the classical pathway which is antibody dependent and the other is the alternative pathway which is independent of the antibody. Both pathways are considered important for the immunological and natural defense mechanisms of fishes against invading pathogens. Although the complement activities of many fishes have been previously studied, the classical pathway of eel Anguilla japonica complement have not been investigated. In this paper, the hemolytic activity of eel serum was investigated by using sheep red blood cells (SRBC) sensitized with eel antiserum. The antiserum was obtained from eel immunized with SRBC suspension as immunogen. The hemolytic activity increased as the agglutinating antibody titer increased. The optimum conditions for hemolytic activity were confirmed at a reaction temperature of 30°C and at pH 7.5. The hemolytic activity was in-activated entirely by heating the serum at 45°C for 30 min, inhibited partially with EDTA, EGTA and zymosan and enhanced with divalent cation Ca2+ and Mg2+.
In general, the complement activity of mammalian has some representative properties like being temperature dependent, heat labile, requiring Ca2+ and Mg2+, and consumption activity by zymosan. In the present investigation, the properties of the antibody dependent hemolytic activity of eel serum were observed to be similar with those of the mammalian. These findings therefore suggest that the hemolytic activity in eel serum is caused by the complement activity.
