Department of Infectious Diseases & Immunology, University of Florida, Gainesville, FL, United States.
Front Immunol. 2021 Jul 7;12:697953. doi: 10.3389/fimmu.2021.697953. eCollection 2021.
Past studies with the live, double-mutant (znBAZ) strain resulted in nearly complete protection of mice against pulmonary challenge with wild-type (wt) a dominant CD8 T cell response. To understand the contribution innate immune cells in priming CD8 T cell responses, mice were nasally dosed with wt , smooth vaccine strain 19 (S19), or znBAZ, and examined for innate immune cell activation. Flow cytometric analysis revealed that znBAZ, but not wt nor S19 infection, induces up to a 5-fold increase in the frequency of IFN-γ-producing NK cells in mouse lungs. These NK cells express increased CXCR3 and Ki67, indicating their recruitment and proliferation subsequent to znBAZ infection. Their activation status was augmented noted by the increased NKp46 and granzyme B, but decreased NKG2A expression. Further analysis demonstrated that both lung caspase-1 inflammatory monocytes and monocyte-derived macrophages secrete chemokines and cytokines responsible for NK cell recruitment and activation. Moreover, neutralizing IL-18, an NK cell-activating cytokine, reduced the znBAZ-induced early NK cell response. NK cell depletion also significantly impaired lung dendritic cell (DC) activation and migration to the lower respiratory lymph nodes (LRLNs). Both lung DC activation and migration to LRLNs were significantly impaired in NK cell-depleted or IFN-γ mice, particularly the CD11b and monocytic DC subsets. Furthermore, znBAZ vaccination significantly induced CD8 T cells, and upon NK cell depletion, CD8 T cells were reduced 3-fold compared to isotype-treated mice. In summary, these data show that znBAZ induces lung IFN-γ NK cells, which plays a critical role in influencing lung DC activation, migration, and promoting protective CD8 T cell development.
过去的研究表明,活的、双重突变体(znBAZ)菌株可使小鼠对野生型(wt)主导的 CD8 T 细胞应答的肺攻击产生几乎完全的保护。为了了解固有免疫细胞在引发 CD8 T 细胞反应中的贡献,用 wt、光滑疫苗株 19(S19)或 znBAZ 鼻内给药小鼠,并检查固有免疫细胞的激活情况。流式细胞术分析显示,znBAZ 而非 wt 或 S19 感染可使小鼠肺部产生 IFN-γ的 NK 细胞频率增加多达 5 倍。这些 NK 细胞表达增加的 CXCR3 和 Ki67,表明它们在 znBAZ 感染后被募集和增殖。它们的激活状态通过增加的 NKp46 和颗粒酶 B,以及减少的 NKG2A 表达来增强。进一步的分析表明,肺 caspase-1 炎性单核细胞和单核细胞衍生的巨噬细胞都分泌趋化因子和细胞因子,负责 NK 细胞的募集和激活。此外,中和 IL-18,一种 NK 细胞激活细胞因子,可减少 znBAZ 诱导的早期 NK 细胞反应。NK 细胞耗竭也显著损害肺树突状细胞(DC)的激活和向下呼吸道淋巴结(LRLN)的迁移。NK 细胞耗竭或 IFN-γ小鼠的肺 DC 激活和向 LRLN 的迁移均显著受损,特别是 CD11b 和单核细胞样 DC 亚群。此外,znBAZ 疫苗接种显著诱导 CD8 T 细胞,并且在 NK 细胞耗竭后,与同型处理的小鼠相比,CD8 T 细胞减少了 3 倍。总之,这些数据表明 znBAZ 诱导肺部 IFN-γ NK 细胞,这在影响肺部 DC 的激活、迁移和促进保护性 CD8 T 细胞的发展中起着关键作用。
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