Center for Cell and Gene Therapy, Baylor College of Medicine, The Methodist Hospital and Texas Children's Hospital, Houston, TX 77030, USA.
Gene Ther. 2013 Sep;20(9):958-62. doi: 10.1038/gt.2013.25. Epub 2013 May 23.
Genetic engineering of T cells for adoptive immunotherapy in cancer patients has shown significant promise. To ensure optimal antitumor activity and safety, the simultaneous expression of multiple genes is frequently required, and short viral-derived 2A sequences are increasingly preferred for this purpose. Concerns exist, however, that these virus-derived sequences may induce unwanted immune responses, and thus diminish persistence of the gene-modified cells after adoptive transfer. Whereas such responses were absent in immunocompromised recipients, potential immunogenicity in immunocompetent individuals remains a concern. We now address whether ex vivo T cell responses can be elicited against the most widely used 2A sequences (2A-Thosea asigna virus (TAV) or 2A-equine rhinitis virus (ERAV), specifically) in immunocompetent individuals. We used a potent ex vivo culture system previously validated to induce T cell responses even against weakly immunogenic antigens. Of the sixteen donors tested, only five released very low levels of interferon-γ in response to 2A-TAV peptide mixtures (single peptide specificity in three donors, adjacent self-antigen peptide specificity in one donor and nonspecific reactivity in one donor). None of them produced cytotoxic activity or responded to 2A-ERAV. These results suggest that exposure to viral-derived 2A sequences is unlikely to produce unwanted T cell responses in immunocompetent individuals and further supports their continued use for studies of human gene therapy.
基因工程 T 细胞用于癌症患者的过继免疫治疗已显示出显著的前景。为了确保最佳的抗肿瘤活性和安全性，通常需要同时表达多个基因，为此越来越多地倾向于使用短的病毒衍生 2A 序列。然而，人们担心这些病毒衍生序列可能会引起不必要的免疫反应，从而降低过继转移后基因修饰细胞的持久性。虽然在免疫功能低下的受者中不存在这种反应，但在免疫功能正常的个体中，潜在的免疫原性仍然是一个问题。我们现在研究的是在免疫功能正常的个体中，针对最广泛使用的 2A 序列（2A-Thosea asigna 病毒 (TAV) 或 2A-马鼻炎病毒 (ERAV））是否可以引发体外 T 细胞反应。我们使用了一种以前经过验证的有效体外培养系统，即使针对弱免疫原性抗原，也能诱导 T 细胞反应。在测试的 16 个供体中，只有 5 个在 2A-TAV 肽混合物（3 个供体的单个肽特异性、1 个供体的相邻自身抗原肽特异性和 1 个供体的非特异性反应性）中释放出非常低水平的干扰素-γ。它们都没有产生细胞毒性活性或对 2A-ERAV 有反应。这些结果表明，在免疫功能正常的个体中，暴露于病毒衍生的 2A 序列不太可能产生不必要的 T 细胞反应，并进一步支持它们继续用于人类基因治疗的研究。
