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Veterinary microbiology
Elsevier
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| Abstract: |
Newcastle disease virus (NDV) classified as an avian paramyxovirus-1 poses a significant risk to the global
poultry sector. This study explored the kinetics of the innate and adaptive immune responses in chickens exposed
to virulent Newcastle Disease Virus (vNDV) genotype VII. A challenge experiment was carried out with both nonvaccinated
and NDV-vaccinated chickens utilizing different vaccination strategies commonly used in the industry.
The four groups of vaccinated birds were administered either two doses of live NDV vaccines, live
vaccines boosted with an inactivated vaccine, the rHVT-NDV-IBDV vaccine alone, or the rHVT-NDV-IBDV vaccine
in conjunction with a live vaccine booster. To assess seven cytokines linked to antiviral and proinflammatory
innate responses quantitative real-time polymerase chain reaction (qRT-PCR) analyses were implemented. The
analyses revealed robust innate immune responses in all cytokines measured in lung and spleen tissues of the
group that received both live and inactivated vaccines. Notably these increases were found to correlate with the
humoral immune response within that same group. Significant transcriptional activity in the lung and spleen
tissues of non-vaccinated chickens at 24 hour post-infection (pi). The most significant upregulations were
identified in toll-like receptor 7 (TLR7), TLR5, interleukin 6 (IL6), chicken interferon-alpha (chIFN-α), and
myxovirus resistance protein 1 (Mx1), which later exhibited a regression. The administration of both live and
inactivated vaccines has proven effective in restoring the suppression or inhibition of vNDV infection across a
wide range of cytokines, including TLR7, TLR5, chIFN-α, Mx1, IL6, and MHC-1. Various vaccination strategies
have been shown to either mitigate or prevent cytokine storms within 24 hour pi in the lungs, spleen, or both, in
certain cytokines such as chIFN-α, Mx1, and IL6. Collectively these results suggest that different vaccination
strategies modify the kinetics and pathophysiological responses associated with vNDV infection in chickens.
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