Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic College of Medicine and Science, Rochester, MN, United States.
Department of Immunology, Mayo Clinic College of Medicine and Science, Rochester, MN, United States.
Front Immunol. 2019 Oct 10;10:2332. doi: 10.3389/fimmu.2019.02332. eCollection 2019.
Tissue resident memory CD8 T cells (T) serve as potent local sentinels and contribute significantly to protective immunity against intracellular mucosal pathogens. While the molecular and transcriptional underpinnings of T differentiation are emerging, how T establishment is regulated by other leukocytes is largely unclear. Here, we observed that expression of PPAR-γ in the myeloid compartment was a negative regulator of CD8 T establishment following influenza virus infection. Interestingly, myeloid deficiency of PPAR-γ resulted in selective impairment of the tissue-resident alveolar macrophage (AM) compartment during primary influenza infection, suggesting that AM are likely negative regulators of CD8 T differentiation. Indeed, influenza-specific CD8 T cell numbers were increased following early, but not late ablation of AM using the CD169-DTR model. Importantly, these findings were specific to the parenchyma of infected tissue as circulating memory T cell frequencies in lung and T and T in spleen were largely unaltered following macrophage ablation. Further, the magnitude of the effector response could not explain these observations. These data indicate local regulation of pulmonary T differentiation is alveolar macrophage dependent. These, findings could aid in vaccine design aimed at increasing T density to enhance protective immunity, or deflating their numbers in conditions where they cause overt or veiled chronic pathologies.
组织驻留记忆 CD8 T 细胞(T)作为有效的局部哨兵,对抵抗细胞内黏膜病原体的保护性免疫有重要贡献。虽然 T 细胞分化的分子和转录基础正在显现,但其他白细胞如何调节 T 细胞的建立在很大程度上尚不清楚。在这里,我们观察到,髓系细胞中 PPAR-γ 的表达是流感病毒感染后 CD8 T 细胞建立的负调节因子。有趣的是,髓系细胞中 PPAR-γ 的缺失导致原发性流感感染期间肺泡巨噬细胞(AM)组织驻留区的选择性受损,这表明 AM 可能是 CD8 T 细胞分化的负调节因子。事实上,使用 CD169-DTR 模型早期而非晚期清除 AM 后,流感特异性 CD8 T 细胞数量增加。重要的是,这些发现是针对感染组织实质的,因为在清除巨噬细胞后,肺和脾中的循环记忆 T 细胞频率以及 T 和 T 细胞基本没有改变。此外,效应应答的幅度不能解释这些观察结果。这些数据表明,肺 T 细胞分化的局部调节依赖于肺泡巨噬细胞。这些发现可能有助于设计旨在增加 T 细胞密度以增强保护性免疫的疫苗,或在它们引起显性或隐性慢性病理的情况下减少它们的数量。