FIG. 2.

Vaccine challenge experiment. Each fish in each group was challenged with 15,000 live I. multifiliis theronts at day 84 after the first injection. Seventy-two percent of the fish (n = 50) immunized with 10 μg of affinity-purified 55-kDa i-antigen (◊) in CFA and IFA and 59.2% of the fish (n = 49) immunized with live I. multifiliis theronts (□) survived the challenge. Negative control fish injected with an immobilization-irrelevant 14-kDa I. multifiliis protein (▵) or BSA (×) in CFA and IFA died by day 16 following challenge.