Revealing differential TCRγδ⁺CD8α⁺ T-cell responses and peptide preferences among various commercial live attenuated infectious bronchitis virus vaccines in chickens

This study demonstrates that commercial IBV vaccines with comparable humoral immunogenicity elicit markedly different cellular immune profiles. We identify TCRγδ⁺CD8α⁺ T cells as the predominant responders following IBV vaccination and show that different vaccine strains establish distinct peptide-specific immune hierarchies, including H120-induced recognition of a highly conserved nucleoprotein peptide (N381–400, 92% conservation) with potential relevance for cross-protection.

These findings highlight the importance of incorporating cellular immune parameters into IBV vaccine evaluation and provide a rationale for evidence-based vaccine selection and optimization of vaccination strategies in poultry.