功能性不同的配对 NK 细胞受体对改变的自身 MHC I 类分子的感应可抵抗小鼠巨细胞病毒 gp34 介导的免疫逃逸。
Altered-Self MHC Class I Sensing via Functionally Disparate Paired NK Cell Receptors Counters Murine Cytomegalovirus gp34-Mediated Immune Evasion.
机构信息
Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA.
Beirne Carter Center for Immunology Research, University of Virginia, Charlottesville, Virginia, USA.
出版信息
J Immunol. 2022 Oct 15;209(8):1545-1554. doi: 10.4049/jimmunol.2200441. Epub 2022 Sep 7.
The murine CMV (MCMV) immunoevasin m04/gp34 escorts MHC class I (MHC I) molecules to the surface of infected cells where these complexes bind Ly49 inhibitory receptors (IRs) and prevent NK cell attack. Nonetheless, certain self-MHC I-binding Ly49 activating and inhibitory receptors are able to promote robust NK cell expansion and antiviral immunity during MCMV infection. A basis for MHC I-dependent NK cell sensing of MCMV-infected targets and control of MCMV infection however remains unclear. In this study, we discovered that the Ly49R activation receptor is selectively triggered during MCMV infection on antiviral NK cells licensed by the Ly49G2 IR. Ly49R activating receptor recognition of MCMV-infected targets is dependent on MHC I D and MCMV gp34 expression. Remarkably, although Ly49R is critical for Ly49G2-dependent antiviral immunity, blockade of the activation receptor in Ly49G2-deficient mice has no impact on virus control, suggesting that paired Ly49G2 MCMV sensing might enable Ly49R NK cells to better engage viral targets. Indeed, MCMV gp34 facilitates Ly49G2 binding to infected cells, and the IR is required to counter gp34-mediated immune evasion. A specific requirement for Ly49G2 in antiviral immunity is further explained by its capacity to license cytokine receptor signaling pathways and enhance Ly49R NK cell proliferation during infection. These findings advance our understanding of the molecular basis for functionally disparate self-receptor enhancement of antiviral NK cell immunity.
小鼠巨细胞病毒(MCMV)免疫逃逸蛋白 m04/gp34 将 MHC I(MHC I)分子运送到感染细胞的表面,这些复合物与 Ly49 抑制性受体(IR)结合,并防止 NK 细胞攻击。尽管如此,某些自身 MHC I 结合的 Ly49 激活和抑制性受体能够在 MCMV 感染期间促进 NK 细胞的强烈扩增和抗病毒免疫。然而,MHC I 依赖性 NK 细胞对 MCMV 感染靶标的感知和对 MCMV 感染的控制的基础仍然不清楚。在这项研究中,我们发现 Ly49R 激活受体在 Ly49G2 IR 许可的抗病毒 NK 细胞受到 MCMV 感染时被选择性地触发。Ly49R 激活受体识别 MCMV 感染的靶标依赖于 MHC I D 和 MCMV gp34 的表达。值得注意的是,尽管 Ly49R 对于 Ly49G2 依赖性抗病毒免疫至关重要,但在 Ly49G2 缺陷小鼠中阻断激活受体对病毒控制没有影响,这表明配对的 Ly49G2 MCMV 感应可能使 Ly49R NK 细胞更好地与病毒靶标结合。事实上,MCMV gp34 促进了 Ly49G2 与感染细胞的结合,而该 IR 对于中和 gp34 介导的免疫逃逸是必需的。Ly49G2 在抗病毒免疫中的特定作用进一步解释了其在许可细胞因子受体信号通路和增强感染期间 Ly49R NK 细胞增殖方面的能力。这些发现提高了我们对功能不同的自身受体增强抗病毒 NK 细胞免疫的分子基础的理解。