2023 journal article

In Ovo Vaccination with Recombinant Herpes Virus of the Turkey-Laryngotracheitis Vaccine Adjuvanted with CpG-Oligonucleotide Provides Protection against a Viral Challenge in Broiler Chickens


By: C. Gaghan n, M. Browning n, A. Fares n , M. Abdul-Careem*, I. Gimeno n  & R. Kulkarni  n

co-author countries: Canada πŸ‡¨πŸ‡¦ United States of America πŸ‡ΊπŸ‡Έ
author keywords: infectious laryngotracheitis; vaccine; protection; CpG oligonucleotide; adjuvant; chickens
Source: Web Of Science
Added: November 13, 2023

Infectious laryngotracheitis (ILT) is an economically important disease in chickens. We previously showed that an in ovo adjuvantation of recombinant herpesvirus of the turkey-Laryngotracheitis (rHVT-LT) vaccine with CpG-oligonucleotides (ODN) can boost vaccine-induced responses in one-day-old broiler chickens. Here, we evaluated the protective efficacy of in ovo administered rHVT-LT + CpG-ODN vaccination against a wild-type ILT virus (ILTV) challenge at 28 days of age and assessed splenic immune gene expression as well as cellular responses. A chicken-embryo-origin (CEO)-ILT vaccine administered in water at 14 days of age was also used as a comparative control for the protection assessment. The results showed that the rHVT-LT + CpG-ODN or the CEO vaccinations provided significant protection against the ILTV challenge and that the level of protection induced by both the vaccines was statistically similar. The protected birds had a significantly upregulated expression of interferon (IFN)Ξ³ or interleukin (IL)-12 cytokine genes. Furthermore, the chickens vaccinated with the rHVT-LT + CpG-ODN or CEO vaccine had a significantly higher frequency of Ξ³Ξ΄ T cells and activated CD4+ or CD8+ T cells, compared to the unvaccinated-ILTV challenge control. Collectively, our findings suggest that CpG-ODN can be used as an effective adjuvant for rHVT-LT in ovo vaccination to induce protective immunity against ILT in broiler chickens.