Xie Zimin, Chen Yingyi, Xie Jun, Du Shanyao, Chen Rongmao, Zheng Yuqin, You Bowen, Feng Min, Liao Ming, Dai Manman
National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China.
National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, Guangdong Provincial Key Laboratory of Zoonosis Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, PR China; UK-China Centre of Excellence for Research on Avian Diseases, Guangzhou 510642, PR China.
Vet Microbiol. 2025 Jan;300:110337. doi: 10.1016/j.vetmic.2024.110337. Epub 2024 Dec 8.
Although the use of inactivated vaccines has kept avian influenza (AI) outbreaks largely under control, they fail to prevent virus shedding. To enhance the efficacy of inactivated H9N2 AIV vaccines (InV), we constructed a multi-epitope recombinant baculovirus (BV-BNT) containing two B cell epitopes and nine T cell epitopes of H9N2 AIV for combined immunization with InV. The results showed that HI titer, IgG and IgM levels, and the percentage of B cells, CD4 T cells, CD8 T cells, and CD4CD8 T cells were significantly higher in the InV+BV-BNT immunization group than the InV immunization group. Besides, the expression levels of IL-1β, IFN-γ, IFN-α, IL-4, IL-13, and CXCLi1 were significantly higher in the InV+BV-BNT group than the InV group. Moreover, four conservative peptides (NP, NP, NS, and NP) significantly stimulated splenocytes to express IFN-γ in the InV+BV-BNT group instead of InV group. After heterologous virus challenging, the percentages of CD4 T and CD8 T cells were significantly upregulated in the InV+BV-BNT group compared to Inv group at 3 DPI. Viral loads in oropharyngeal of the InV+BV-BNT group was significantly lower than that in the InV group at 3 days post-infection (DPI). Furthermore, compared to the InV group, the virus positivity rate of oropharyngeal and cloacal swabs in the InV+BV-BNT group was lower at 5 DPI, with none positive at 7 DPI. Hence, this study indicated that the combined immunization of InV and BV-BNT could induce stronger humoral and cellular immune responses, shorten the detoxification period and reduce viral load compared to Inv alone, which suggests BV-BNT could act as a supplementary vaccine to potentially address the protection deficiency of the H9N2 inactivated vaccine.
尽管灭活疫苗的使用已在很大程度上控制了禽流感（AI）疫情，但它们无法阻止病毒排出。为提高灭活H9N2禽流感病毒疫苗（InV）的效力，我们构建了一种多表位重组杆状病毒（BV-BNT），其包含H9N2禽流感病毒的两个B细胞表位和九个T细胞表位，用于与InV联合免疫。结果显示，InV+BV-BNT免疫组的血凝抑制（HI）效价、IgG和IgM水平以及B细胞、CD4 T细胞、CD8 T细胞和CD4CD8 T细胞的百分比均显著高于InV免疫组。此外，InV+BV-BNT组中IL-1β、IFN-γ、IFN-α、IL-4、IL-13和CXCLi1的表达水平显著高于InV组。此外，在InV+BV-BNT组中，四种保守肽（NP、NP、NS和NP）显著刺激脾细胞表达IFN-γ，而InV组则无此现象。异源病毒攻击后，与InV组相比，InV+BV-BNT组在感染后3天（DPI）时CD4 T细胞和CD8 T细胞的百分比显著上调。InV+BV-BNT组在感染后3天（DPI）时口咽部位的病毒载量显著低于InV组。此外，与InV组相比，InV+BV-BNT组在5 DPI时口咽和泄殖腔拭子的病毒阳性率较低，在7 DPI时均无阳性。因此，本研究表明，与单独使用InV相比，InV和BV-BNT联合免疫可诱导更强的体液和细胞免疫反应，缩短排毒期并降低病毒载量，这表明BV-BNT可作为一种补充疫苗，潜在地解决H9N2灭活疫苗的保护缺陷问题。
