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5.7 Specificity of the humoral immune response in Atlantic salmon
400
5.6
Session 5
THE HUMORAL IMMUNE RESPONSE PATHOGEN VIBRIO SALMONICIDA
IN
ATLANTIC
SALMON
AGAINST
THE
T. Jo/rgensen, S. Espelid, K. Stensvag and J. Bo/gwald, The Foundation of Applied Research at the University of Tromso/, 9001 Tromso/, Norway. Vaccination of farmed salmon (Salmo salar) with the agent Vibrio salmonicida has demonstrated a specific protection above 90% against cold-water vibriosis. Although the immune mechanisms involved have not been elucidated, the antibody response as well as the immunological protection seen is dependent on a particular surface antigen from V. salmonicida. This antigen (VSPl) is well characterized as being composed of protein units (n=10-15, 40 kda each) and lipopolysaccharides (LPS). Approximately 95% of salmon antibodies against V. salmonicida react with the VSPI complex. Moreover, the bulk-specificity of these salmon antibodies is directed against the LPS moiety in VSPI, as shown in ELISA using highly purified LPS as antigen. Performing antibody-binding competition studies (ELISA), including monoclonal antibodies (MAB) to VSPI, the fine-specificity of polyclonal salmon antisera was found to be correlated to the binding of one particular MAB (out of fourteen), indicating a narrow antibody repertoire in salmon antibodies to V. salmonicida. Data concerning uptake and degradation (processing) of V. salmonicida by phagocytic cells (macrophages) in vitro, were also be discussed. 5.7
SPECIFICITY
OF THE HUMORAL
IMMUNE
RESPONSE
IN ATLANTIC
SALMON
Johan Glette, *Leiv S. Havarstein, Karen E. Christie and *Curt Endresen, Norbio A/S; and "Laboratory of Biotechnology, 5001 Bergen, Norway. Atlantic salmon (Salmo salar) were injected intraperitoneally either with formalin-killed Vibrio salmonicida or with the N1 strain of IPN virus. Blood samples were drawn two weeks after the second immunization, and an indirect ELISA assay was used to quantitate specific antibodies in the serum. Specific antibodies were detected in serum from vaccinated salmons. The Vibrio salmonicida antiserum cross reacted slightly with two strains of Vibrio anauillarum. This result was verified using the Western blotting technique. However, no cross reaction was observed with two other fish pathogens (Yersinia ruckeri and Aeromonas salmonicida). The virus antiserum reacted strongly with the homologous N1 strain, but very slightly with three other strains of IPNV (Jasper, Sp and Ab). Neutralization tests confirmed these results. Our results show that the humoral immune response of Atlantic salmon is specific. Assuming that specific antibodies participate in the defence against pathogens, these results are important for the development of vaccines.
5.6
Session 5
THE HUMORAL IMMUNE RESPONSE PATHOGEN VIBRIO SALMONICIDA
IN
ATLANTIC
SALMON
AGAINST
THE
T. Jo/rgensen, S. Espelid, K. Stensvag and J. Bo/gwald, The Foundation of Applied Research at the University of Tromso/, 9001 Tromso/, Norway. Vaccination of farmed salmon (Salmo salar) with the agent Vibrio salmonicida has demonstrated a specific protection above 90% against cold-water vibriosis. Although the immune mechanisms involved have not been elucidated, the antibody response as well as the immunological protection seen is dependent on a particular surface antigen from V. salmonicida. This antigen (VSPl) is well characterized as being composed of protein units (n=10-15, 40 kda each) and lipopolysaccharides (LPS). Approximately 95% of salmon antibodies against V. salmonicida react with the VSPI complex. Moreover, the bulk-specificity of these salmon antibodies is directed against the LPS moiety in VSPI, as shown in ELISA using highly purified LPS as antigen. Performing antibody-binding competition studies (ELISA), including monoclonal antibodies (MAB) to VSPI, the fine-specificity of polyclonal salmon antisera was found to be correlated to the binding of one particular MAB (out of fourteen), indicating a narrow antibody repertoire in salmon antibodies to V. salmonicida. Data concerning uptake and degradation (processing) of V. salmonicida by phagocytic cells (macrophages) in vitro, were also be discussed. 5.7
SPECIFICITY
OF THE HUMORAL
IMMUNE
RESPONSE
IN ATLANTIC
SALMON
Johan Glette, *Leiv S. Havarstein, Karen E. Christie and *Curt Endresen, Norbio A/S; and "Laboratory of Biotechnology, 5001 Bergen, Norway. Atlantic salmon (Salmo salar) were injected intraperitoneally either with formalin-killed Vibrio salmonicida or with the N1 strain of IPN virus. Blood samples were drawn two weeks after the second immunization, and an indirect ELISA assay was used to quantitate specific antibodies in the serum. Specific antibodies were detected in serum from vaccinated salmons. The Vibrio salmonicida antiserum cross reacted slightly with two strains of Vibrio anauillarum. This result was verified using the Western blotting technique. However, no cross reaction was observed with two other fish pathogens (Yersinia ruckeri and Aeromonas salmonicida). The virus antiserum reacted strongly with the homologous N1 strain, but very slightly with three other strains of IPNV (Jasper, Sp and Ab). Neutralization tests confirmed these results. Our results show that the humoral immune response of Atlantic salmon is specific. Assuming that specific antibodies participate in the defence against pathogens, these results are important for the development of vaccines.