Evaluación de la respuesta inmune heteróloga conferida por la vacuna Brucella abortus RB51 en modelo murino contra Brucella canis cepa RM6/66.
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Date
2025
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Universidad de Concepción
Abstract
Brucella canis es el agente etiológico de la brucelosis canina, una enfermedad zoonótica con una seroprevalencia del 7,3 % en perros en Chile. Su presentación clínica es inespecífica, manifestándose principalmente como infertilidad. Ante la ausencia de tratamientos eficaces y vacunas aprobadas, en este estudio se evaluó la inmunogenicidad y la protección heteróloga conferida por la vacuna Brucella abortus RB51 en ratones BALB/c frente a la cepa B. canis RM6/66, con énfasis en la respuesta inmune a nivel de mucosas. Los animales fueron inmunizados por vía intranasal o intraperitoneal con B. abortus RB51. La inmunogenicidad se evaluó mediante la titulación y funcionalidad de los anticuerpos, junto con la determinación de los niveles de citocinas, mientras que la protección conferida se analizó a través del recuento bacteriano en bazo tras el desafío con B. canis RM6/66 por vías intravaginal e intraperitoneal. La inmunización intranasal indujo niveles de IgA anti-B. canis capaces de aglutinar al patógeno y activar el complemento, además de estimular la producción de TNF-α e IFN-γ. Los ratones inmunizados por vía intranasal presentaron un índice de protección de 2,13 en bazo. Estos resultados sugieren que esta administración podría constituir una estrategia eficaz para la prevención de la brucelosis canina, destacando la relevancia de profundizar en los mecanismos de inmunidad de mucosas inducidos por esta vacuna.
Brucella canis is the etiological agent of canine brucellosis, a zoonotic disease with a seroprevalence of 7.3% in dogs in Chile. Its clinical presentation is usually nonspecific, most commonly manifested as infertility. Due to the absence of effective treatments and approved vaccines, this study evaluated the immunogenicity and heterologous protection conferred by the Brucella abortus RB51 vaccine in BALB/c mice against the B. canis RM6/66 strain, with an emphasis on the mucosal immune response. Animals were immunized intranasally or intraperitoneally with B. abortus RB51. Immunogenicity was assessed by antibody titers and functional activity, together with cytokine quantification, while protection was analyzed through bacterial counts in the spleen after challenge with B. canis RM6/66 via intravaginal or intraperitoneal routes. Intranasal immunization induced anti-B. canis IgA antibodies capable of agglutinating the pathogen and activating complement, as well as stimulating the production of TNF-α and IFN-γ. Mice immunized intranasally showed a splenic protection index of 2.13. These results suggest that intranasal administration of B. abortus RB51 could represent an effective strategy for the prevention of canine brucellosis, highlighting the importance of further investigation into the mucosal immune mechanisms induced by this vaccine.
Brucella canis is the etiological agent of canine brucellosis, a zoonotic disease with a seroprevalence of 7.3% in dogs in Chile. Its clinical presentation is usually nonspecific, most commonly manifested as infertility. Due to the absence of effective treatments and approved vaccines, this study evaluated the immunogenicity and heterologous protection conferred by the Brucella abortus RB51 vaccine in BALB/c mice against the B. canis RM6/66 strain, with an emphasis on the mucosal immune response. Animals were immunized intranasally or intraperitoneally with B. abortus RB51. Immunogenicity was assessed by antibody titers and functional activity, together with cytokine quantification, while protection was analyzed through bacterial counts in the spleen after challenge with B. canis RM6/66 via intravaginal or intraperitoneal routes. Intranasal immunization induced anti-B. canis IgA antibodies capable of agglutinating the pathogen and activating complement, as well as stimulating the production of TNF-α and IFN-γ. Mice immunized intranasally showed a splenic protection index of 2.13. These results suggest that intranasal administration of B. abortus RB51 could represent an effective strategy for the prevention of canine brucellosis, highlighting the importance of further investigation into the mucosal immune mechanisms induced by this vaccine.
Description
Tesis presentada para optar al grado de Magíster en Ciencias con mención en Microbiología.
Keywords
Brucelosis, Perros, Vacunas, Inmunogenética