Bin Dhuban Khalid, d'Hennezel Eva, Nashi Emil, Bar-Or Amit, Rieder Sadiye, Shevach Ethan M, Nagata Satoshi, Piccirillo Ciriaco A
Department of Microbiology and Immunology, McGill University, Montreal, Quebec H3G 1A4, Canada; Federation of Clinical Immunology Centre of Excellence, Research Institute of the McGill University Health Centre, Montreal, Quebec H3G 1A4, Canada;
Division of Allergy and Immunology, McGill University Health Centre, Montreal, Quebec H2C 2P2, Canada;
J Immunol. 2015 Apr 15;194(8):3687-96. doi: 10.4049/jimmunol.1401803. Epub 2015 Mar 11.
Two distinct subsets of CD4(+)Foxp3(+) regulatory T (Treg) cells have been described based on the differential expression of Helios, a transcription factor of the Ikaros family. Efforts to understand the origin and biological roles of these Treg populations in regulating immune responses have, however, been hindered by the lack of reliable surface markers to distinguish and isolate them for subsequent functional studies. Using a single-cell cloning strategy coupled with microarray analysis of different Treg functional subsets in humans, we identify the mRNA and protein expression of TIGIT and FCRL3 as a novel surface marker combination that distinguishes Helios(+)FOXP3(+) from Helios(-)FOXP3(+) memory cells. Unlike conventional markers that are modulated on conventional T cells upon activation, we show that the TIGIT/FCRL3 combination allows reliable identification of Helios(+) Treg cells even in highly activated conditions in vitro as well as in PBMCs of autoimmune patients. We also demonstrate that the Helios(-)FOXP3(+) Treg subpopulation harbors a larger proportion of nonsuppressive clones compared with the Helios(+)FOXP3(+) cell subset, which is highly enriched for suppressive clones. Moreover, we find that Helios(-) cells are exclusively responsible for the productions of the inflammatory cytokines IFN-γ, IL-2, and IL-17 in FOXP3(+) cells ex vivo, highlighting important functional differences between Helios(+) and Helios(-) Treg cells. Thus, we identify novel surface markers for the consistent identification and isolation of Helios(+) and Helios(-) memory Treg cells in health and disease, and we further reveal functional differences between these two populations. These new markers should facilitate further elucidation of the functional roles of Helios-based Treg heterogeneity.
基于伊卡洛斯家族转录因子Helios的差异表达，已描述了CD4(+)Foxp3(+)调节性T（Treg）细胞的两个不同亚群。然而，由于缺乏可靠的表面标志物来区分和分离这些Treg群体以进行后续功能研究，了解这些Treg群体在调节免疫反应中的起源和生物学作用的努力受到了阻碍。通过单细胞克隆策略结合对人类不同Treg功能亚群的微阵列分析，我们确定TIGIT和FCRL3的mRNA和蛋白表达是一种新的表面标志物组合，可将Helios(+)FOXP3(+)与Helios(-)FOXP3(+)记忆细胞区分开来。与传统T细胞激活后会被调节的传统标志物不同，我们发现即使在体外高度激活的条件下以及自身免疫患者的外周血单核细胞（PBMC）中，TIGIT/FCRL3组合也能可靠地识别Helios(+) Treg细胞。我们还证明，与高度富集抑制性克隆的Helios(+)FOXP3(+)细胞亚群相比，Helios(-)FOXP3(+) Treg亚群中不具有抑制作用的克隆比例更大。此外，我们发现Helios(-)细胞在体外专门负责FOXP3(+)细胞中炎性细胞因子IFN-γ、IL-2和IL-17的产生，这突出了Helios(+)和Helios(-) Treg细胞之间重要的功能差异。因此，我们确定了用于在健康和疾病中一致识别和分离Helios(+)和Helios(-)记忆Treg细胞的新表面标志物，并进一步揭示了这两个群体之间的功能差异。这些新标志物应有助于进一步阐明基于Helios的Treg异质性的功能作用。
