Evaluation of epitope vaccine based on phage display technology for largemouth bass virus

Largemouth bass virus (LMBV), as a serious aquatic animal virus, has resulted in significant economic losses to the bass farming industry. Currently, vaccination is considered an effective measure for preventing LMBV infection and enhancing largemouth bass (Micropterus salmoides) production. In the study, we determined the targets of specific antibodies in serum from the LMBV survivors by panning a Ph.D.-12 phage library, and high-affinity targeted peptides (P1 and P2) were synthesized. Afterwards, the epitope vaccines were prepared by combining peptides with Freund's complete adjuvant, and inoculated into largemouth bass for in vivo validation. The results indicated that the specific phage enrichment rate was up to 487 times after four rounds of panning, and epitope vaccines showed a good immune response. Furthermore, immune-related parameters in largemouth bass immunized with Adjuvant-P1 and Adjuvant-P2 (20 mu g/g) epitope vaccines were considerably greater than in those immunized with Adjuvant-P1 and Adjuvant-P2 (5 mu g/g) epitope vaccines. During 14 days post infection, the survival of largemouth bass treated with Adjuvant-P1 and Adjuvant-P2 (20 mu g/g) were 55.18% and 51.72%, respectively. These results indicated that P1 and P2 can serve as candidate antigens for the prevention and treatment of LMBV.