背景:猪甲型流感病毒(SwIAV)构成了经济和大流行威胁,新型有效疫苗的开发具有至关重要的意义。我们评估了单独使用植物衍生的纳米颗粒佐剂(Nano-11)[Nano11-SwIAV]或与干扰素基因的合成刺激剂(STING)激动剂ADU-S100(NanoS100-SwIAV)组合的分裂猪甲型流感病毒(SwIAV)H1N1抗原的性能。通过肌内(IM)或皮内(ID)途径对无特定病原体(SPF)的猪进行两次疫苗接种,并用毒性异源SwIAVH1N1-OH7病毒攻击。
结果:用NanoS100-SwIAV接种IM或ID的动物血清中交叉反应性IgG和IgA滴度显著增加,攻击后第6天的鼻腔分泌物和支气管肺泡灌洗液(DPC6)。此外,NanoS100-SwIAVID疫苗接种,即使是疫苗接种剂量的一半,气管支气管淋巴结(TBLN)中CXCL10+骨髓细胞的频率显着增加,和IFNγ+效应记忆T辅助/记忆细胞,IL-17A+总T辅助细胞/记忆细胞,中枢和效应记忆T辅助/记忆细胞,IL-17A+总细胞毒性T淋巴细胞(CTL),与Nano11-SwIAV组相比,血液中的早期效应CTL表现出潜在的剂量节省效应,并在外周诱导强烈的IL-17AT辅助/记忆(Th17)反应。然而,IFNγ+晚期效应CTL和效应记忆T辅助细胞/记忆细胞的频率,IL-17A+总CTL,晚期效应CTL,和血液中的CXCL10+骨髓细胞,以及肺CXCL10+浆细胞样树突状细胞在NanoS100-SwIAVIM疫苗接种的猪中增加。在攻击后,在基于Nano-11的IM疫苗接种的TBLN中观察到IL-4和IL-6mRNA的表达增加。此外,在通过DPC6接种的NanoS100-SwIAVIM疫苗中,肺部和鼻道中的攻击病毒载量未被检测到,同时在DPC6时,肺部宏观损伤减少,肺部中的病毒中和滴度显著升高.然而,NanoS100-SwIAVID疫苗接种物表现出鼻道中攻击病毒滴度的显着降低和肺中攻击病毒的显着降低。
结论:尽管H1N1病毒和H1N1病毒之间存在巨大的遗传差异(77%的HA基因同一性),NanoS100佐剂疫苗引发交叉保护性细胞介导的免疫反应,提示这种组合佐剂在诱导猪交叉保护性免疫中的潜在作用。
BACKGROUND: Swine influenza A viruses (SwIAVs) pose an economic and pandemic threat, and development of novel effective vaccines is of critical significance. We evaluated the performance of split swine influenza A virus (SwIAV) H1N2 antigens with a plant-derived nanoparticle adjuvant alone (Nano-11) [Nano11-SwIAV] or in combination with the synthetic stimulator of interferon genes (STING) agonist ADU-S100 (NanoS100-SwIAV). Specific pathogen free (SPF) pigs were vaccinated twice via intramuscular (IM) or intradermal (ID) routes and challenged with a virulent heterologous SwIAV H1N1-OH7 virus.
RESULTS: Animals vaccinated IM or ID with NanoS100-SwIAV had significantly increased cross-reactive IgG and IgA titers in serum, nasal secretion and bronchoalveolar lavage fluid at day post challenge 6 (DPC6). Furthermore, NanoS100-SwIAV ID vaccinates, even at half the vaccine dose compared to their IM vaccinated counterparts, had significantly increased frequencies of CXCL10+ myeloid cells in the tracheobronchial lymph nodes (TBLN), and IFNγ+ effector memory T-helper/memory cells, IL-17A+ total T-helper/memory cells, central and effector memory T-helper/memory cells, IL-17A+ total cytotoxic T-lymphocytes (CTLs), and early effector CTLs in blood compared with the Nano11-SwIAV group demonstrating a potential dose-sparing effect and induction of a strong IL-17A+ T-helper/memory (Th17) response in the periphery. However, the frequencies of IFNγ+ late effector CTLs and effector memory T-helper/memory cells, IL-17A+ total CTLs, late effector CTLs, and CXCL10+ myeloid cells in blood, as well as lung CXCL10+ plasmacytoid dendritic cells were increased in NanoS100-SwIAV IM vaccinated pigs. Increased expression of IL-4 and IL-6 mRNA was observed in TBLN of Nano-11 based IM vaccinates following challenge. Furthermore, the challenge virus load in the lungs and nasal passage was undetectable in NanoS100-SwIAV IM vaccinates by DPC6 along with reduced macroscopic lung lesions and significantly higher virus neutralization titers in lungs at DPC6. However, NanoS100-SwIAV ID vaccinates exhibited significant reduction of challenge virus titers in nasal passages and a remarkable reduction of challenge virus in lungs.
CONCLUSIONS: Despite vast genetic difference (77% HA gene identity) between the H1N2 and H1N1 SwIAV, the NanoS100 adjuvanted vaccine elicited cross protective cell mediated immune responses, suggesting the potential role of this combination adjuvant in inducing cross-protective immunity in pigs.