Department of Microbiology and.
Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY.
Blood Adv. 2019 Jul 23;3(14):2153-2163. doi: 10.1182/bloodadvances.2019000292.
Assessment of the quality and the breadth of antigen (Ag)-specific memory T cells in human samples is of paramount importance to elucidate the pathogenesis and to develop new treatments in various diseases. T-cell receptor (TCR) signal strength, primarily controlled by TCR affinity, affects many fundamental aspects of T-cell biology; however, no current assays for detection of Ag-specific CD8 T cells can assess their TCR signal strength in human samples. Here, we provide evidence that interferon regulatory factor 4 (IRF4), a transcription factor rapidly upregulated in correlation with TCR signal strength, permits the assessment of the TCR signal strength of Ag-specific CD8 T cells in human peripheral blood mononuclear cells (PBMCs). Coexpression of IRF4 and CD137 sensitively detected peptide-specific CD8 T cells with extremely low background in PBMCs stimulated for 18 hours with MHC class I peptides. Our assay revealed that human memory CD8 T cells with high-affinity TCRs have an intrinsic ability to highly express CD25. Furthermore, HIV-specific CD8 T cells in chronic HIV subjects were found to display primarily low-affinity TCRs with low CD25 expression capacity. Impairment in the functions of HIV-specific CD8 T cells might be associated with their suboptimal TCR signals, as well as impaired responsiveness to interleukin-2.
评估人类样本中抗原（Ag）特异性记忆 T 细胞的质量和广度对于阐明发病机制和开发各种疾病的新治疗方法至关重要。T 细胞受体（TCR）信号强度主要受 TCR 亲和力控制，影响 T 细胞生物学的许多基本方面；然而，目前尚无检测 Ag 特异性 CD8 T 细胞的方法可以评估其在人类样本中的 TCR 信号强度。在这里，我们提供的证据表明，干扰素调节因子 4（IRF4）是一种与 TCR 信号强度迅速相关上调的转录因子，可用于评估人类外周血单核细胞（PBMC）中 Ag 特异性 CD8 T 细胞的 TCR 信号强度。IRF4 和 CD137 的共表达灵敏地检测到在 MHC 类 I 肽刺激 18 小时后 PBMC 中具有极低背景的肽特异性 CD8 T 细胞。我们的检测方法显示，具有高亲和力 TCR 的人类记忆 CD8 T 细胞具有高度表达 CD25 的内在能力。此外，在慢性 HIV 患者中发现 HIV 特异性 CD8 T 细胞主要显示低亲和力 TCR，其 CD25 表达能力低。HIV 特异性 CD8 T 细胞功能障碍可能与其亚最佳 TCR 信号以及对白细胞介素 2 的反应受损有关。
