T cells are considered pivotal in the pathology of multiple sclerosis (MS), but their function and antigen specificity are unknown. To unravel the role of T cells in MS pathology, we performed a comprehensive analysis on T cells recovered from paired blood, cerebrospinal fluid (CSF), normal-appearing white matter (NAWM) and white matter lesions (WML) from 27 MS patients with advanced disease shortly after death. The differentiation status of T cells in these compartments was determined by ex vivo flow cytometry and immunohistochemistry. T-cell reactivity in short-term T-cell lines (TCL), generated by non-specific stimulation of T cells recovered from the same compartments, was determined by intracellular cytokine flow cytometry. Central memory T cells predominated in CSF and effector memory T cells were enriched in NAWM and WML. WML-derived CD8⁺ T cells represent chronically activated T cells expressing a cytotoxic effector phenotype (CD95L and granzyme B) indicative for local antigenic stimulation (CD137). The same lesions also contained higher CD8⁺ T-cell frequencies expressing co-inhibitory (TIM3 and PD1) and co-stimulatory (ICOS) T-cell receptors, yet no evidence for T-cell senescence (CD57) was observed. The oligoclonal T-cell receptor (TCR) repertoire, particularly among CD8⁺ T cells, correlated between TCL generated from anatomically separated WML of the same MS patient, but not between paired NAWM and WML. Whereas no substantial T-cell reactivity was detected towards seven candidate human MS-associated autoantigens (cMSAg), brisk CD8⁺ T-cell reactivity was detected in multiple WML-derived TCL towards autologous Epstein–Barr virus (EBV) infected B cells (autoBLCL). In one MS patient, the T-cell response towards autoBLCL in paired intra-lesional TCL was dominated by TCRVβ2⁺CD8⁺ T cells, which were localized in the parenchyma of the respective tissues expressing a polarized TCR and CD8 expression suggesting immunological synapse formation in situ. Collectively, the data suggest the involvement of effector memory cytotoxic T cells recognizing antigens expressed by autoBLCL, but not the assayed human cMSAg, in WML of MS patients.

T细胞被认为是多发性硬化症（MS）病理学中的关键，但其功能和抗原特异性尚不清楚。为了揭示T细胞在MS病理学中的作用，我们对从27例MS患者中配对的血液，脑脊液（CSF），正常出现的白质（NAWM）和白质病变（WML）中回收的T细胞进行了全面分析。死后不久即进入晚期疾病。通过离体流式细胞术和免疫组织化学确定这些隔室中T细胞的分化状态。通过细胞内细胞因子流式细胞术确定了短期T细胞系（TCL）中的T细胞反应性，该细胞是通过非特异性刺激从相同区室回收的T细胞而产生的。在CSF中占主导地位的中央记忆T细胞和效应记忆T细胞富含NAWM和WML。WML衍生的CD8⁺ T细胞代表慢性激活的T细胞，其表达指示局部抗原刺激（CD137）的细胞毒性效应表型（CD95L和颗粒酶B）。相同的病变还包含较高的CD8 ⁺ T细胞频率，表达共抑制性（TIM3和PD1）和共刺激性（ICOS）T细胞受体，但未观察到T细胞衰老（CD57）的证据。寡克隆T细胞受体（TCR）组成，特别是CD8 ⁺ T细胞，与同一MS患者的解剖分离WML产生的TCL之间相关，而在成对的NAWM和WML之间不相关。鉴于未检测到对7种候选人MS相关自身抗原（cMSAg）的实质性T细胞反应，CD8 ⁺在多个WML衍生的TCL中检测到针对自体爱泼斯坦-巴尔病毒（EBV）感染的B细胞（autoBLCL）的T细胞反应性。在一名MS患者中，成对的病灶内TCL中对autoBLCL的T细胞反应主要由TCRVβ2 ⁺ CD8 ⁺ T细胞决定，TCRVβ2 ⁺ CD8 ⁺ T细胞位于表达极化TCR和CD8表达的各个组织的实质中，提示免疫原性突触的形成。原地。总体而言，数据表明在MS患者的WML中涉及识别autoBLCL表达的抗原的效应器记忆细胞毒性T细胞，但未检测到人cMSAg。