Immunogenicity and Efficacy of CpG-Adjuvanted In-Ovo Recombinant HVT-LT and FPV-LT Vaccines Against Infectious Laryngotracheitis Challenge in 14-Day-Old Broiler Chickens.
- 1Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, 1060 William Moore Drive, Raleigh, NC 27606, USA.
- 2Health Research Innovation Center 2C58, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
Abstract
Recombinant herpesvirus of turkey laryngotracheitis (rHVT-LT) and fowlpox virus (rFPV)-LT in-ovoin-ovo vaccines are used for ILT control in broiler chickens. Previously, we showed that in-ovoin-ovo CpG-oligodeoxynucleotide (CpG-ODN) adjuvantation of rHVT-LT can protect broilers against ILT at 28 days of age. Here, we evaluated the immunogenicity and protective efficacy of in-ovoin-ovo CpG-ODN-adjuvanted rHVT-LT and rFPV-LT in broilers when challenged at 14 days of age. Eighteen experimental groups incorporated CpG-ODN-only treatments or those receiving rHVT-LT or rFPV-LT with/without CpG-ODN or non-CpG control ODN in-ovoin-ovo, followed by ILTV challenge at 14 days of age. While none of the vaccinated groups provided significant clinical protection, rHVT-LT+CpG-ODN vaccination showed a numerical reduction (p = 0.0710) in disease severity following ILTV challenge compared with the unvaccinated control. CpG-ODN-only or CpG-ODN-adjuvanted vaccinations followed by challenge resulted in increased (p < 0.05) tracheal and/or splenic TLR21, IL-12, or IFNγ transcription, indicating TLR-mediated antiviral adjuvant effects. Furthermore, CpG-ODN+rHVT-LT/rFPV-LT groups receiving ILTV had increased (p < 0.05) splenic frequencies of macrophages, γδ T cells, B cells, and activated CD4⁺/CD8⁺ T cells. Collectively, our findings indicate that in-ovo CpG-ODN adjuvantation with recombinant-vectored ILT vaccines can induce measurable immune activation and a trend toward reduced ILT disease severity following early ILTV challenge in broiler chickens.
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BibTeX
@article{gaghan2026immunogenicity,
title = {{Immunogenicity and Efficacy of CpG-Adjuvanted In-Ovo Recombinant HVT-LT and FPV-LT Vaccines Against Infectious Laryngotracheitis Challenge in 14-Day-Old Broiler Chickens.}},
author = {Carissa Gaghan and Matthew Browning and Aakriti Tyagi and Pok Man Chan and Mohamed Faizal Abdul-Careem and Isabel M Gimeno and Raveendra R Kulkarni},
journal = {Viruses},
year = {2026},
month = oct,
doi = {10.3390/v18101096},
url = {https://europepmc.org/article/MED/42944016},
note = {CC BY},
}
RIS
TY - JOUR
TI - Immunogenicity and Efficacy of CpG-Adjuvanted In-Ovo Recombinant HVT-LT and FPV-LT Vaccines Against Infectious Laryngotracheitis Challenge in 14-Day-Old Broiler Chickens.
AU - Carissa Gaghan
AU - Matthew Browning
AU - Aakriti Tyagi
AU - Pok Man Chan
AU - Mohamed Faizal Abdul-Careem
AU - Isabel M Gimeno
AU - Raveendra R Kulkarni
PY - 2026
DA - 2026/10/03
JO - Viruses
DO - 10.3390/v18101096
UR - https://europepmc.org/article/MED/42944016
AB - Recombinant herpesvirus of turkey laryngotracheitis (rHVT-LT) and fowlpox virus (rFPV)-LT in-ovoin-ovo vaccines are used for ILT control in broiler chickens. Previously, we showed that in-ovoin-ovo CpG-oligodeoxynucleotide (CpG-ODN) adjuvantation of rHVT-LT can protect broilers against ILT at 28 days of age. Here, we evaluated the immunogenicity and protective efficacy of in-ovoin-ovo CpG-ODN-adjuvanted rHVT-LT and rFPV-LT in broilers when challenged at 14 days of age. Eighteen experimental groups incorporated CpG-ODN-only treatments or those receiving rHVT-LT or rFPV-LT with/without CpG-ODN or non-CpG control ODN in-ovoin-ovo, followed by ILTV challenge at 14 days of age. While none of the vaccinated groups provided significant clinical protection, rHVT-LT+CpG-ODN vaccination showed a numerical reduction (p = 0.0710) in disease severity following ILTV challenge compared with the unvaccinated control. CpG-ODN-only or CpG-ODN-adjuvanted vaccinations followed by challenge resulted in increased (p < 0.05) tracheal and/or splenic TLR21, IL-12, or IFNγ transcription, indicating TLR-mediated antiviral adjuvant effects. Furthermore, CpG-ODN+rHVT-LT/rFPV-LT groups receiving ILTV had increased (p < 0.05) splenic frequencies of macrophages, γδ T cells, B cells, and activated CD4⁺/CD8⁺ T cells. Collectively, our findings indicate that in-ovo CpG-ODN adjuvantation with recombinant-vectored ILT vaccines can induce measurable immune activation and a trend toward reduced ILT disease severity following early ILTV challenge in broiler chickens.
SN - 1999-4915
ER -