Avian influenza viruses (AIVs) infect a wide range of hosts, including humans and many avian species. Efforts have been made to control this pathogen in chickens using vaccination programs, but that has been met with varying degrees of success. Therefore, identification of more efficacious vaccination strategies is warranted. This study was undertaken to investigate the potential effects of probiotics on the immunogenicity of a beta-propiolactone-whole inactivated virus (WIV) vaccine of H9N2 subtype adjuvanted with the Toll-like receptor-21 ligand, CpG oligodeoxynucleotides 2007 (CpG). Eighty-four 1-day-old White Leghorn layers were allocated into six groups. Two out of six groups received a mixture of probiotic Lactobacillus spp. (PROB) biweekly from days 1 35 of age. Chickens were intramuscularly vaccinated with WIV either alone or adjuvanted with AddaVax™ (WIV+Add) or CpG (WIV+CpG), and one group received saline (phosphate-buffered saline). Primary and secondary vaccinations occurred at days 14 and 28 of age, respectively. The results revealed that the group that received probiotics and was vaccinated with CpG-adjuvanted WIV H9N2 vaccine had higher hemagglutination inhibition titers than the other treatment groups at days 14 and 21 postprimary vaccination. Probiotics did not induce higher IgM or IgY titers in chickens receiving the WIV vaccine only. Concerning their effect on cell-mediated immune responses, probiotics enhanced interferon-gamma (IFN-γ) gene expression and significantly increased secretion of IFN-γ protein by splenocytes in chickens vaccinated with CpG-adjuvanted WIV H9N2. Together, these findings suggest the use of probiotics to enhance the immunogenicity of CpG-adjuvanted WIV H9N2 vaccines. Additional studies are required to better understand the specific interactions between probiotics and the gut microbiota and different types of cells of the gastrointestinal tract to decipher the underlying mechanisms of how probiotics modulate immune responses to vaccines.

中文翻译：

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益生菌乳酸杆菌增强灭活 H9N2 流感病毒疫苗在鸡体内的免疫原性

禽流感病毒 (AIV) 感染范围广泛的宿主，包括人类和许多禽类物种。已经努力使用疫苗接种程序控制鸡体内的这种病原体，但取得了不同程度的成功。因此，有必要确定更有效的疫苗接种策略。本研究旨在调查益生菌对辅以 Toll 样受体 21 配体 CpG 寡脱氧核苷酸 2007 (CpG) 的 H9N2 亚型 β-丙内酯-全灭活病毒 (WIV) 疫苗的免疫原性的潜在影响。84 只 1 日龄的 White Leghorn 鸡被分成六组。六组中有两组接受了益生菌乳酸杆菌的混合物spp. （概率）从第 1 天到第 35 天每两周一次。鸡单独或辅以 AddaVax™ (WIV+Add) 或 CpG (WIV+CpG) 肌肉内接种 WIV，一组接受盐水（磷酸盐缓冲盐水）。初次和二次疫苗接种分别发生在第 14 天和第 28 天。结果显示，在初次接种后第 14 天和第 21 天，接受益生菌并接种 CpG 佐剂 WIV H9N2 疫苗的组比其他治疗组具有更高的血凝抑制效价。益生菌不会在仅接受 WIV 疫苗的鸡中诱导更高的 IgM 或 IgY 滴度。关于它们对细胞介导的免疫反应的影响，在接种 CpG 佐剂的 WIV H9N2 的鸡中，益生菌增强了干扰素-γ (IFN-γ) 基因的表达，并显着增加了脾细胞中 IFN-γ 蛋白的分泌。总之，这些发现表明使用益生菌来增强 CpG 佐剂 WIV H9N2 疫苗的免疫原性。需要更多的研究来更好地了解益生菌与肠道微生物群和不同类型的胃肠道细胞之间的特定相互作用，以破译益生菌如何调节对疫苗的免疫反应的潜在机制。