Phylogeny and species comparison as tools for understanding antigen recog-nition by human γδ T-cells

系统发育和物种比较作为了解人类 γδ T 细胞抗原识别的工具

• 批准号: 412843862
• 负责人: Professor Dr. Thomas Herrmann
• 金额: --
• 依托单位: Institut für Virologie und Immunbiologie
• 依托单位国家: 德国
• 项目类别: Research Units
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/412843862?language=en
• 关键词: Phylogeny; species; comparison; tools; understanding

γδ T-cell antigen-receptors (γδTCR) emerged together with the other RAG-dependent antigen receptors and are found in nearly all jawed vertebrate species. There is an increasing interest in clinical use of γδTCR-expressing cells (γδ T cells) but the antigens and the modes of antigen-recognition by γδ T-cell antigen-receptors (TCRs) are poorly understood. γδ T cells vary massively in phenotype and function and subpopulations of γδ T cells are found only in certain species and are often de-fined by their V-gene usage. One of those subpopulations are human Vγ9Vδ2 T cells whose eponymous TCRs sense so-called phosphoantigens (PAgs), which are phos-phorylated host or microbial metabolites of isoprenoid synthesis. The strongest natu-ral PAg is HMBPP which drives Vγ9Vδ2 T-cell-activation and -expansion in infections like tuberculosis and malaria. A rather weak and host cell-produced PAg is IPP which accumulates in some tumor cells or after treatment with amino-bisphosphonates (e.g. zoledronate). This IPP accumulation sensitizes the cells for the tumoricidal activity of Vγ9Vδ2 T-cells. For more than 20 years Vγ9Vδ2 T-cells were believed to be restricted to higher pri-mates but we found such cells in the alpaca although missing in murine rodents. Vγ9Vδ2 TCR do not bind PAgs directly but sense host cell changes induced by PAg -binding to the intracellular domain of BTN (butyrophilin) 3 molecules. In humans BTN3A1 cooperates with its isoforms BTN3A2 and BTN3A3 while alpaca possesses a single BTN3 which integrates the functions of the three isoforms. Apart from BTN3A1, BTN2A1-expression by the target cells is also essential for PAg-mediated activation of Vγ9Vδ2 T cells. However, molecular events and signaling cascades in-volved in the TCR-mediated activation are poorly understood. We will create BTN3-chimeric molecules and mutants to identify minimal molecular requirements of PAg-sensing and to assign protein domains to certain function by analysis with biochemi-cal and imaging techniques. Similarly, we will use species differences to investigate the interaction between BTN3 and BTN2A1 molecules and that of BTNs and TCR. In parallel TCR-BTN interaction shall be studied also in other species. To reconstruct TCR-BTN coevolution BTN-domains will be inserted into human molecules and test-eds for functionality. Compared will be BTNs and TCRs of human, alpaca, camels and the thirteen-lined squirrel, one of the few rodents possessing genes for BTN2, BTN3 and TCR-Vγ9. Finally, we want to learn whether Vγ9Vδ2 T cells from different species, namely human, alpaca and Old-World camelids, share common features apart from their TCR. To this end transcriptomics of Vγ9Vδ2 T cells from different species will be performed aiming to understand what makes a Vγ9Vδ2 T cell a Vγ9Vδ2 T cell apart from its TCR.

γδ t细胞抗原受体（γδ tcr）与其他rag依赖的抗原受体一起出现，几乎在所有的颌类脊椎动物中都有发现。人们对γδ tcr表达细胞（γδ T细胞）的临床应用越来越感兴趣，但对γδT细胞抗原受体（TCRs）的抗原和抗原识别模式知之甚少。γδ T细胞在表型和功能上差异很大，γδ T细胞亚群仅在某些物种中发现，通常由它们的v基因使用来定义。其中一个亚群是人类Vγ9Vδ2 T细胞，其同名的tcr感知所谓的磷酸抗原（PAgs），这是磷磷酸化的宿主或微生物合成类异戊二烯的代谢物。最强的天然PAg是HMBPP，它在结核病和疟疾等感染中驱动v - γ - 9v - δ2 t细胞活化和扩增。宿主细胞产生的一种相当弱的PAg是IPP，它在一些肿瘤细胞中或用氨基双膦酸盐（如唑来膦酸盐）治疗后积累。这种IPP积累使细胞对v γ - 9v - δ2 t细胞的杀瘤活性敏感。20多年来，人们一直认为v γ - 9v δ2 t细胞只存在于高等灵长类动物中，但我们在羊驼中发现了这种细胞，而在小鼠中却没有。v - γ - 9v - δ2 TCR不直接结合PAg，但能感知PAg与细胞内BTN (butyrophilin) 3分子结合引起的宿主细胞变化。在人类中，BTN3A1与其异构体BTN3A2和BTN3A3协同工作，而羊驼只有一个BTN3，它整合了三个异构体的功能。除了BTN3A1，靶细胞表达btn2a1也是pag介导的v - γ 9v δ2 T细胞活化所必需的。然而，参与tcr介导的激活的分子事件和信号级联知之甚少。我们将创建btn3嵌合分子和突变体，以确定pag传感的最小分子要求，并通过生化和成像技术分析分配蛋白质结构域的某些功能。同样，我们将利用物种差异来研究BTN3和BTN2A1分子之间以及btnn和TCR之间的相互作用。同时，TCR-BTN的相互作用也应在其他物种中进行研究。为了重建TCR-BTN协同进化，btn结构域将被插入到人类分子中并进行功能测试。将比较人类、羊驼、骆驼和十三纹松鼠的btn和tcr，十三纹松鼠是少数具有BTN2、BTN3和TCR-Vγ9基因的啮齿动物之一。最后，我们想了解不同物种的Vγ9Vδ2 T细胞，即人类、羊驼和旧大陆骆驼，除了TCR外，是否有共同的特征。为此，将对来自不同物种的v - γ 9v δ2 T细胞进行转录组学研究，以了解除了TCR之外，v - γ 9v δ2 T细胞成为v - γ 9v δ2 T细胞的原因。