The Analysis of Live-Attenuated Piscirickettsia salmonis Vaccine Reveals the Short-Term Upregulation of Innate and Adaptive Immune Genes in Atlantic Salmon (Salmo salar): An In Situ Open-Sea Cages Study

Piscirickettsia salmonis, the etiological agent of the Salmon Rickettsial Septicemia (SRS), is one the most serious health problems for the Chilean salmon industry. Typical antimicrobial strategies used against P. salmonis include antibiotics and vaccines, but these applications have largely failed. A few years ago, the first attenuated-live vaccine against SRS (ALPHA JECT LiVac® SRS vaccine) was released to the market. However, there is no data about the agents involved in the activation of the immune response induced under field conditions. Therefore, in this study we evaluated the expression profile of a set of gene markers related to innate and adaptive immunity in the context of a cellular response in Atlantic salmon (Salmo salar) reared under productive farm conditions and immunized with a live-attenuated vaccine against P. salmonis. We analyzed the expression at zero, 5-, 15- and 45-days post-vaccination (dpv). Our results reveal that the administration of the attenuated live SRS LiVac vaccine induces a short-term upregulation of the cellular-mediated immune response at 5 dpv modulated by the upregulation of ifnα, ifnγ, and the cd4 and cd8α T cell surface markers. In addition, we also registered the upregulation of il-10 and tgfβ. Altogether, the results suggest that a balanced activation of the immune response took place only at early times post-vaccination (5 dpv). The scope of this short-term upregulation of the cellular-mediated immune response against a natural outbreak in fish subjected to productive farm conditions deserves further research.

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Infectivity of a Scottish isolate of Piscirickettsia salmonis for Atlantic salmon Salmo salar and immune response of salmon to this agent

Diseases of Aquatic Organisms ◽

10.3354/dao060097 ◽

2004 ◽

Vol 60 ◽

pp. 97-103 ◽

Cited By ~ 21

Author(s):

TH Birkbeck ◽

S Rennie ◽

D Hunter ◽

LA Laidler ◽

S Wadsworth

Keyword(s):

Immune Response ◽

Atlantic Salmon ◽

Salmo Salar ◽

Atlantic Salmon Salmo Salar ◽

Piscirickettsia Salmonis

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Assessing the Immune Response of Atlantic Salmon (Salmo salar) after the Oral Intake of Alginate-Encapsulated Piscirickettsia salmonis Antigens

Vaccines ◽

10.3390/vaccines8030450 ◽

2020 ◽

Vol 8 (3) ◽

pp. 450

Author(s):

Daniela Sotomayor-Gerding ◽

José Miguel Troncoso ◽

Alejandro Pino ◽

Felipe Almendras ◽

Mónica Rubilar Diaz

Keyword(s):

Immune Response ◽

Atlantic Salmon ◽

Salmo Salar ◽

Low Dose ◽

Oral Vaccine ◽

Fish Growth ◽

High Dose ◽

Fish Feed ◽

Atlantic Salmon Salmo Salar ◽

Piscirickettsia Salmonis

Salmon rickettsial septicaemia (SRS) is the infectious disease that produces the highest losses in the Chilean salmon industry. As a new strategy for the control of SRS outbreaks, in this study we evaluated the effect of alginate-encapsulated Piscirickettsia salmonis antigens (AEPSA) incorporated in the feed as an oral vaccine to induce the immune response in Atlantic salmon (Salmo salar). Fish were distributed into three vaccination groups (injectable, oral high dose, oral low dose). Feed intake and fish growth were recorded during the trial. The P. salmonis-specific IgM levels in blood plasma were measured by ELISA. Alginate microparticles containing the antigen were effectively incorporated in fish feed to produce the oral vaccine. Incorporation of AEPSA did not affect the palatability of the feed or the fish appetite. Furthermore, the oral vaccine did not have a negative effect on fish growth. Finally, the oral vaccine (high and low dose) produced an acquired immune response (IgM) similar to the injectable vaccine, generating a statistically significant increase in the IgM levels at 840-degree days for both experimental groups. These findings suggest that AEPSA incorporated in the feed can be an effective alternative to boost the immune response in Atlantic salmon (S. salar).

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