TY - JOUR

T1 - High immunogenicity of virus-like particles (VLPs) decorated with Aeromonas salmonicida VapA antigen in rainbow trout

AU - Yang, Jeong In

AU - Sepúlveda, Dagoberto

AU - Vardia, Irina

AU - Skov, Jakob

AU - Goksøyr, Louise

AU - Sander, Adam F.

AU - Lorenzen, Niels

N1 - Publisher Copyright: Copyright © 2023 Yang, Sepúlveda, Vardia, Skov, Goksøyr, Sander and Lorenzen.

PY - 2023

Y1 - 2023

N2 - The Gram-negative bacterium A. salmonicida is the causal agent of furunculosis and used to be one of the most loss-causing bacterial infections in the salmonid aquaculture industry with a mortality rate of about 90% until the 1990s, when an inactivated vaccine with mineral oil as adjuvant was successfully implemented to control the disease. However, the use of this vaccine is associated with inflammatory side effects in the peritoneal cavity as well as autoimmune reactions in Atlantic salmon, and incomplete protection has been reported in rainbow trout. We here aimed at developing and testing a recombinant alternative vaccine based on virus-like particles (VLPs) decorated with VapA, the key structural surface protein in the outer A-layer of A. salmonicida. The VLP carrier was based on either the capsid protein of a fish nodavirus, namely red grouper nervous necrotic virus (RGNNV) or the capsid protein of Acinetobacter phage AP205. The VapA and capsid proteins were expressed individually in E. coli and VapA was fused to auto-assembled VLPs using the SpyTag/SpyCatcher technology. Rainbow trout were vaccinated/immunized with the VapA-VLP vaccines by intraperitoneal injection and were challenged with A. salmonicida 7 weeks later. The VLP vaccines provided protection comparable to that of a bacterin-based vaccine and antibody response analysis demonstrated that vaccinated fish mounted a strong VapA-specific antibody response. To our knowledge, this is the first demonstration of the potential use of antigen-decorated VLPs for vaccination against a bacterial disease in salmonids.

AB - The Gram-negative bacterium A. salmonicida is the causal agent of furunculosis and used to be one of the most loss-causing bacterial infections in the salmonid aquaculture industry with a mortality rate of about 90% until the 1990s, when an inactivated vaccine with mineral oil as adjuvant was successfully implemented to control the disease. However, the use of this vaccine is associated with inflammatory side effects in the peritoneal cavity as well as autoimmune reactions in Atlantic salmon, and incomplete protection has been reported in rainbow trout. We here aimed at developing and testing a recombinant alternative vaccine based on virus-like particles (VLPs) decorated with VapA, the key structural surface protein in the outer A-layer of A. salmonicida. The VLP carrier was based on either the capsid protein of a fish nodavirus, namely red grouper nervous necrotic virus (RGNNV) or the capsid protein of Acinetobacter phage AP205. The VapA and capsid proteins were expressed individually in E. coli and VapA was fused to auto-assembled VLPs using the SpyTag/SpyCatcher technology. Rainbow trout were vaccinated/immunized with the VapA-VLP vaccines by intraperitoneal injection and were challenged with A. salmonicida 7 weeks later. The VLP vaccines provided protection comparable to that of a bacterin-based vaccine and antibody response analysis demonstrated that vaccinated fish mounted a strong VapA-specific antibody response. To our knowledge, this is the first demonstration of the potential use of antigen-decorated VLPs for vaccination against a bacterial disease in salmonids.

KW - A. salmonicida

KW - aquaculture

KW - fish diseases

KW - furunculosis

KW - recombinant vaccine

KW - Virus-like particles (VLPs)

UR - http://www.scopus.com/inward/record.url?scp=85161088509&partnerID=8YFLogxK

U2 - 10.3389/fimmu.2023.1139206

DO - 10.3389/fimmu.2023.1139206

M3 - Journal article

C2 - 37283749

AN - SCOPUS:85161088509

VL - 14

JO - Frontiers in Immunology

JF - Frontiers in Immunology

SN - 1664-3224

M1 - 1139206

ER -