An effective live attenuated vaccine against Streptococcus agalactiae infection in farmed Nile tilapia (Oreochromis niloticus).
Fish Shellfish Immunol
; 98: 853-859, 2020 Mar.
Article
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| MEDLINE
| ID: mdl-31751658
ABSTRACT
Streptococcus agalactiae is an important pathogen associated with various aquatic animals, especially tilapia. Streptococcosis has greatly limited the healthy development of tilapia aquaculture in recent times. The development of novel effective vaccines is important for the prevention and control of streptococcosis in fish. We previously constructed a non-encapsulated S. agalactiae strain â³cps by the in-frame deletion method. Here, we evaluated whether this mutant â³cps is safe for tilapia and suitable for protection against streptococcosis. We observed that the â³cps strain was non-pathogenic to tilapia, and there was no reversion of virulence when it was passaged in tilapia. Moreover, the â³cps strain survived for at least 11 d in the main immune organs of tilapia. The tilapia vaccinated via intraperitoneal (IP) injection with â³cps strain induced a high antibody titer, and the IgM antibody levels were significantly higher in the vaccinated group than in the control group. The vaccination protected tilapia against the S. agalactiae challenge with a relative percent survival of 90.47%. In addition, tilapia immunized with the â³cps strain showed significantly higher expression level of IFN-γ, IL-1ß, MyD88, IgM, and MHC-Iα in the head kidney than those in the control during the entire observation period. The expression of MHC-IIß was inhibited during 1-7 d of immunization. These results revealed that the â³cps strain is able to induce humoral and cell-mediated immune response in tilapia. Therefore, the strain â³cps has a broad application prospect as a target for attenuation in vaccine development.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Infecciones Estreptocócicas
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Streptococcus agalactiae
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Vacunas Estreptocócicas
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Cíclidos
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Inmunidad Humoral
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Enfermedades de los Peces
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Inmunidad Celular
Límite:
Animals
Idioma:
En
Revista:
Fish Shellfish Immunol
Asunto de la revista:
BIOLOGIA
/
MEDICINA VETERINARIA
Año:
2020
Tipo del documento:
Article