| Research Abstract |
The early development of self-defense mechanisms walking catfish Clarias batrachus has been investigated from two different standpoints : development of lymphatic organs, and maternal immunity. In this fishes, kidney and thymus lymphopoiesis occur in the early stages of larval development, while spleen development is delayd. These observations suggest the low immuno-reactivity in fish larvae by their own immune systm.
On the other hand the existence of egg IgM has been noted catfish. This was indicated by SDS-PAGE and western blotting technique using monoclonal antibody raised against H-chain of catfish IgM.Egg IgM is thought to be caused from maternal origin, and similar observations has been also made in carp Cyprinus carpio and red sea bream Pagras major by us. In particular, egg IgM from red sea bream vaccinated with Vibrio anguillarum exhibits anti-Vibrio activity, which demostrates the existence of maternal immunity. The egg IgM molecule is not necessarily the same as the plasma IgM molecules, as the H chain of egg IgM in catfish as well as carp has a lower molecular weight. Further investigations are needed to clarify the homogeneity of egg IgM to the plasma type IgM.
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