T cell activation and differentiation is modulated by a CD6 domain 1 antibody Itolizumab.
T cell activation and differentiation is modulated by a CD6 domain 1 antibody Itolizumab.
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DOI：
10.1371/journal.pone.0180088
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Nair P
中科院分区：
文献类型：
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作者：
Bughani U;Saha A;Kuriakose A;Nair R;Sadashivarao RB;Venkataraman R;Patel S;Deshchougule AT;S SK;Montero E;Pai HV;Palanivelu DV;Melarkode R;Nair P
CD6 与 T 细胞调节相关，并与多种自身免疫性疾病有关。我们之前证明 Itolizumab 是一种 CD6 结构域 1 (CD6D1) 特异性人源化单克隆抗体，可抑制用抗 CD3 抗体刺激或与 ALCAM 共同刺激的 T 淋巴细胞的增殖和细胞因子产生。产生异常 IL-17 的 CD4+ 辅助 T 细胞 (Th17) 已被确定为某些炎症性自身免疫性疾病（包括牛皮癣）发病机制的关键。伊托珠单抗已证明对已知由 IL-17 驱动的发病机制的人类疾病有效。在这里，在体外实验中，我们表明，在 Th17 极化环境中使用抗 CD3 和抗 CD28 共刺激激活人类 PBMC 的第 3 天，15-35% 的 CD4+ T 细胞过度表达 CD6，并且分化的 Th17 细胞建立。添加 Itolizumab 可减少 T 细胞向 Th17 细胞的活化和分化，并减少 IL-17 的产生。这些效应与关键转录因子 pSTAT3 和 RORγT 的减少有关。此外，在这些条件下的转录分析研究表明，Itolizumab 主要通过减少细胞周期、DNA 转录和翻译相关基因来抑制 T 细胞活化。为了了解这种抑制的机制，我们评估了这种抗人 CD6D1 mAb 对 ALCAM-CD6 以及 TCR 介导的 T 细胞激活的影响。我们发现伊托珠单抗而非其 F(ab')2 片段直接抑制 CD6 受体过度磷酸化，并导致相关 ZAP70 激酶和对接蛋白 SLP76 随后减少。由于 Itolizumab 与仅在人类和黑猩猩上表达的 CD6 结合，因此我们开发了一种与小鼠 CD6D1 特异性结合的抗体。该抗体成功降低了小鼠模型中实验性自身免疫性脑炎的发病率。这些结果将 CD6 定位为维持 T 细胞活化和分化的关键分子以及调节自身免疫性疾病的重要靶标。
CD6 is associated with T-cell modulation and is implicated in several autoimmune diseases. We previously demonstrated that Itolizumab, a CD6 domain 1 (CD6D1) specific humanized monoclonal antibody, inhibited the proliferation and cytokine production by T lymphocytes stimulated with anti-CD3 antibody or when co-stimulated with ALCAM. Aberrant IL-17 producing CD4+ helper T-cells (Th17) have been identified as pivotal for the pathogenesis of certain inflammatory autoimmune disorders, including psoriasis. Itolizumab has demonstrated efficacy in human diseases known to have an IL-17 driven pathogenesis. Here, in in vitro experiments we show that by day 3 of human PBMC activation using anti-CD3 and anti-CD28 co-stimulation in a Th17 polarizing milieu, 15–35% of CD4+ T-cells overexpress CD6 and there is an establishment of differentiated Th17 cells. Addition of Itolizumab reduces the activation and differentiation of T cells to Th17 cells and decreases production of IL-17. These effects are associated with the reduction of key transcription factors pSTAT3 and RORγT. Further, transcription analysis studies in these conditions indicate that Itolizumab suppressed T cell activation by primarily reducing cell cycle, DNA transcription and translation associated genes. To understand the mechanism of this inhibition, we evaluated the effect of this anti-human CD6D1 mAb on ALCAM-CD6 as well as TCR-mediated T cell activation. We show that Itolizumab but not its F(ab’)2 fragment directly inhibits CD6 receptor hyper-phosphorylation and leads to subsequent decrease in associated ZAP70 kinase and docking protein SLP76. Since Itolizumab binds to CD6 expressed only on human and chimpanzee, we developed an antibody binding specifically to mouse CD6D1. This antibody successfully ameliorated the incidence of experimental autoimmune encephalitis in the mice model. These results position CD6 as a key molecule in sustaining the activation and differentiation of T cells and an important target for modulating autoimmune diseases.