Recombinant resuscitation-promoting factor protein of Nocardia seriolae, a promissing vaccine candidate for largemouth bass (Micropterus salmoides).

Affiliation

Hoang HH(1), Wang PC(2), Chen SC(3).
Author information:
(1)Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung, 91201, Taiwan. Electronic address: [Email]
(2)Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung, 91201, Taiwan; Southern Taiwan Fish Disease Centre, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung, 91201, Taiwan; International Degree Program of Ornamental Fish Science and Technology, International College, National Pingtung University of Science and Technology, No. 1, Shuefu Road, Neipu, Pingtung, 91201, Taiwan. Electronic address: [Email]
(3)Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung, 91201, Taiwan; Southern Taiwan Fish Disease Centre, National Pingtung University of Science and Technology, No. 1 Shuefu Road, Neipu, Pingtung, 91201, Taiwan; International Degree Program of Ornamental Fish Science and Technology, International College, National Pingtung University of Science and Technology, No. 1, Shuefu Road, Neipu, Pingtung, 91201, Taiwan; Research Centre for Animal Biologics, National Pingtung University of Science and Technology, Pingtung, Taiwan. Electronic address: [Email]

Abstract

Nocardia seriolae is an important pathogenic bacterium that causes nocardiosis in various fish species and leads to economic losses in the fish industry. To develop an effective subunit vaccine against nocardial infection, the truncated resuscitation-promoting factor (tRPF) of N. seriolae was selected and recombinantly produced using the Escherichia coli expression system. Western blotting results indicated that the recombinant protein could be strongly recognised by largemouth bass anti-N. seriolae antibodies. The protective efficacy of tRPF recombinant protein was assessed in combination with the commercial adjuvant Montanide™ ISA 763 A VG. The results showed that emulsified tRPF + ISA significantly induced high serum antibody response and serum lysozyme activity in the vaccinated fish. Quantitative reverse transcription polymerase chain reaction analysis indicated that tRPF + ISA could notably enhance the expression of immune-related genes in both the head kidney and spleen of the vaccinated fish. Finally, vaccinated largemouth bass displayed higher immuno-protection with a relative percent survival of 69.23% compared to the control groups. Taken together, the combination of tRPF + ISA is an ideal vaccine candidate against N. seriolae infection.