Protection against H9N2 challenge in chickens via Salmonella with a focA mutation delivered by a dendritic cell-targeted avian influenza virus NA protein tetramer

作者：Chongbo Ge, Yan Sun, Qiyu Guo, Gerui Zhang, Futing Jia, Tongyu Zhang, Yawen Tian, Wenfeng Wang, Yingkai He, Tianrui Yang, Yupeng Gao, Yuxi Zhang, Yuhang Zhang, Mingyue Wang, Junjie Gong, Haibin Huang, Zhannan Wang, Chunfeng Wang, Yanlong Jiang · 发表于：Microbiology Spectrum · 年份：2025 · DOI：10.1128/spectrum.01421-25 · 被引用次数：3 · 研究领域：Viral gastroenteritis research and epidemiology、Influenza Virus Research Studies、Salmonella and Campylobacter epidemiology

ABSTRACT Vaccination is considered one of the most effective methods for preventing avian influenza. The influenza neuraminidase (NA) enzyme is a promising candidate for a conserved influenza vaccine, offering long-term and effective cross-protection against the disease. The aim of this study is to develop a Salmonella -vectored vaccine with strong protective efficacy against H9N2 avian influenza virus. We utilized the antibiotic-free balanced-lethal system of regulated delayed-lysis Salmonella (χ11218) as the starting strain to construct a focA gene-deleted Salmonella (χYL57) strain. To optimize the vaccine design, we fused a tetravalent NA protein (tetramer-NA) with a chicken dendritic cell-targeting peptide (chDCpep) and delivered it via χ11218 or χYL57, yielding the candidate vaccine strains S323 or ΔS323, respectively. The results revealed that the successful synthesis of tetramer-NA proteins could be detected using nonreducing western blotting and that the presence of chDCpep could dramatically increase the maturation of chicken bone marrow-derived dendritic cells. The focA deletion enhanced bacterial escape from macrophages in vitro and bacterial colonization in vivo . After oral immunization, the combination of chDCpep and focA gene deletion efficiently improved the humoral and mucosal immune responses. Additionally, CD4 and CD8 T cell proliferation in the chicken spleen significantly increased, with elevated intracellular interleukin-4 and interferon-γ mRNA levels. A...