In order to know the true survival of fish postvaccination,
we did challenge experiment at 1000 days when the
antibody had declined down. Our results showed that the RPS
was 64.3%, 42.9%, and 10.7% at a dose of 50 mg/fish, 100 mg/fish
and 20 mg/fish, respectively at 1000 days. These indicated that
there was relevance between immune dosage and memory cells. I