Different immunization routes induce protection against Aeromonas salmonicida through different immune mechanisms in rainbow trout

TY - ABST

T1 - Different immunization routes induce protection against Aeromonas salmonicida through different immune mechanisms in rainbow trout

AU - Villumsen, Kasper Rømer

AU - Raida, Martin Kristian

PY - 2013/6/24

Y1 - 2013/6/24

N2 - Throughout the development of modern aquaculture, furunculosis caused by infection with the bacterial pathogen Aeromonas salmonicida, has posed a major threat to the production of salmonid fish. For decades immunoprophylactic tools against A. salmonicida have been a focus of international research in fish immunology and vaccinology, resulting in the development of both oral, immersion and injectable vaccine strategies over time. Applying mineral oil adjuvants, injectable vaccines inducing high levels of protection in salmon (Salmo salar) rose to prominence in the 1990’s. In general injectable, adjuvanted vaccines have been shown to induce long-lasting increases in specific antibody levels. In general the majority of the published work concerning vaccination against A. salmonicida has been conducted on salmon. Using injectable oil-adjuvanted vaccines, we have previously shown that the induced level of protection against experimental A. salmonicida infection in rainbow trout was positively correlated with the antibody levels immediately prior to the infection. The prolonged presence of specific antibodies and this correlation indicate an important role for specific antibodies in vaccine-induced protection against A. salmonicida. The effect of immersion vaccination against A. salmonicida has been questioned over time. While some have presented excellent protection as a result of immersion vaccines, others have reported limited or absent protective effects. We have performed experiments on the protection induced by immersion vaccination of rainbow trout against A. salmonicida, including an ELISA protocol investigating the antibody levels from vaccination until challenge. Here we present data showing that rainbow trout immunized via a mucosal route induce a high level of protection, similar to that of injected vaccines, but without a significant increase in specific antibody levels. Since this protection seems to be independent of antibodies, it appears that the two different immunization routes induce protection via two protective mechanisms varying in their dependence on specific antibodies.

AB - Throughout the development of modern aquaculture, furunculosis caused by infection with the bacterial pathogen Aeromonas salmonicida, has posed a major threat to the production of salmonid fish. For decades immunoprophylactic tools against A. salmonicida have been a focus of international research in fish immunology and vaccinology, resulting in the development of both oral, immersion and injectable vaccine strategies over time. Applying mineral oil adjuvants, injectable vaccines inducing high levels of protection in salmon (Salmo salar) rose to prominence in the 1990’s. In general injectable, adjuvanted vaccines have been shown to induce long-lasting increases in specific antibody levels. In general the majority of the published work concerning vaccination against A. salmonicida has been conducted on salmon. Using injectable oil-adjuvanted vaccines, we have previously shown that the induced level of protection against experimental A. salmonicida infection in rainbow trout was positively correlated with the antibody levels immediately prior to the infection. The prolonged presence of specific antibodies and this correlation indicate an important role for specific antibodies in vaccine-induced protection against A. salmonicida. The effect of immersion vaccination against A. salmonicida has been questioned over time. While some have presented excellent protection as a result of immersion vaccines, others have reported limited or absent protective effects. We have performed experiments on the protection induced by immersion vaccination of rainbow trout against A. salmonicida, including an ELISA protocol investigating the antibody levels from vaccination until challenge. Here we present data showing that rainbow trout immunized via a mucosal route induce a high level of protection, similar to that of injected vaccines, but without a significant increase in specific antibody levels. Since this protection seems to be independent of antibodies, it appears that the two different immunization routes induce protection via two protective mechanisms varying in their dependence on specific antibodies.

M3 - Conference abstract for conference

T2 - International Conference of Fish and Shellfish Immunology

Y2 - 24 June 2013 through 28 June 2013

ER -