Protection against bovine respiratory syncytial virus in calves vaccinated with adjuvanted modified live vaccine administered in the face of maternal antibody.
Vaccine
; 38(2): 298-308, 2020 01 10.
Article
em En
| MEDLINE
| ID: mdl-31668818
ABSTRACT
Bovine respiratory syncytial virus (BRSV) is major viral contributor to bovine respiratory disease (BRD). BRD is a major cause of morbidity and mortality in all classes of cattle but particularly young beef and dairy calves. Passive antibodies not only help protect the calf against infection, but may interfere with the immune responses following vaccination. The purpose of this study was to evaluate the efficacy of an adjuvanted modified live virus (MLV) vaccine in the presence of well-defined maternal passive immunity. Calves were vaccinated at approximately 1â¯month of age and challenged ~90â¯days later when BRSV systemic antibodies were ≤14. Body temperature was lower at 6 and 7â¯days post challenge and other clinical signs were also lower in the vaccinates. Nasal viral shed was 3-4 times lower in the vaccinated animals as measured by virus isolation and polymerase chain reaction (PCR) and peaked 5â¯days post challenge compared to the controls (who peaked at days 6 and 7). On day 8 following challenge, animals were necropsied, and lung lobes were scored and tested for virus by PCR and indirect fluorescent assay (IFA). There was a 25-fold reduction in PCR virus detection in vaccinates and two of the vaccinated calves' lungs were PCR negative. Only 29.4% of vaccinated calves were BRSV positive on IFA testing at necropsy, while 87.5% of control calves were BRSV positive. Vaccinated calves developed a mucosal BRSV IgA response with over 50% of the vaccinated calves having IgA prior to challenge and all vaccinated calves were positive following challenge. Additionally, vaccination stimulated the production of Interferon gamma (IFN-γ) in mononuclear cells to prime the immune system. This study established that an adjuvanted MLV vaccine could provide protection against BRSV as measured by clinical, virological, and pathological parameters while also activating both mucosal and systemic immunity.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Doenças dos Bovinos
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Vírus Sincicial Respiratório Bovino
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Infecções por Vírus Respiratório Sincicial
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Vacinas contra Vírus Sincicial Respiratório
Limite:
Animals
Idioma:
En
Revista:
Vaccine
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos