Autoimmune vitiligo as a roadmap to melanoma therapy

描述（由申请人提供）：在自身免疫性白癜风中，黑素细胞被识别黑素细胞分化抗原（包括MART-1和gp 100）的细胞毒性T细胞破坏。这导致皮肤和头发的进行性脱色。然而，这种疾病可能使人衰弱和美容毁容，色素脱失过程背后的有效免疫应答对于黑色素瘤患者是非常理想的。在恶性黑色素瘤中，浸润肿瘤的T细胞经常识别白癜风中涉及的相同分化抗原，但所产生的抗肿瘤免疫应答很少导致实际肿瘤消退，如果发生，这种肿瘤消退也可能伴随着皮肤的进行性色素脱失（白斑）。白癜风和黑色素瘤中T细胞反应性之间的这种差异可能是在黑色素瘤的情况下响应于自身抗原的T细胞的克隆缺失的结果，而高亲和力T细胞被异常地引入自身免疫性白癜风的循环中。待检验的主要假设是，来自主动脱色患者皮肤的T细胞比来自黑素瘤肿瘤的T细胞对黑素细胞更具反应性，并且这种增强的功效可以至少部分归因于更高亲和力T细胞受体的表达。为了检验这一假设，将从任一来源分离T细胞，增殖和克隆，鉴定靶抗原（集中于gp 100和MART-1）并进行功能测定。将来自与gp 100或MART-1反应的HLA-A*0201限制性克隆的T细胞受体基因克隆到逆转录病毒载体中，并在相同的背景下（在Jurkat细胞中）表达，以进一步表征TCR对差异反应性的相对贡献。最后，将在体内模型中测试差异T细胞亲合力。高亲和力T细胞受体基因将在患者PBL中表达，并引入用来自同一患者的黑素瘤肿瘤细胞攻击的免疫缺陷小鼠中。将测量肿瘤收缩，并通过免疫组织学分析部分组织。目前的项目将提供深入了解的因素，定义一个有效的免疫反应，黑色素细胞在白癜风，而不是在黑色素瘤中遇到的燃烧的问题。重要的是，在逆转录病毒载体中克隆高亲和力T细胞受体可能适合于引入患者PBL用于治疗恶性黑素瘤。

DESCRIPTION (provided by applicant): In autoimmune vitiligo, melanocytes are destroyed by cytotoxic T cells that recognize melanocyte differentiation antigens including MART-1 and gp100. This leads to progressive depigmentation of the skin and hair. However debilitating and cosmetically disfiguring this disease may be, the effective immune response underlying the depigmentation process is very desirable for melanoma patients. In malignant melanoma, T cells infiltrating the tumors frequently recognize the same differentiation antigens involved in vitiligo, yet the anti-tumor immune response that is mounted seldom leads to actual tumor regression and if it does, such tumor regression can be accompanied by progressive depigmentation of the skin (leukoderma) as well. This difference among T cell reactivity in vitiligo and melanoma is potentially a consequence of clonal deletion of T cells responding to self-antigens in the case of melanoma, whereas high affinity T cells are aberrantly introduced into the circulation in autoimmune vitiligo. The main hypothesis to be tested is that T cells derived from skin of actively depigmenting patients are more reactive towards melanocytic cells than T cells derived from melanoma tumors, and that such enhanced efficacy can be ascribed at least in part to the expression of higher affinity T cell receptors. To test this hypothesis, T cells will be isolated from either source, propagated and cloned, the target antigens identified (focussing on gp100 and MART-1) and subjected to functional assays. The T cell receptor genes from HLA-A*0201 restricted clones reactive with gp100 or MART-1 will be cloned into retroviral vectors and expressed against the same background (in Jurkat cells) for further characterization of the relative contribution of the TCR to differential reactivity. Finally, differential T cell avidity will be put to the test in an In Vivo model. High affinity T cell receptor genes will be expressed in patient PBL and introduced into immunodeficient mice challenged with melanoma tumor cells from the same patient. Tumor shrinkage will be measured and part of the tissue will be analyzed by immunohistology. The current project will provide insight into the burning question of factors defining an efficient immune response to melanocytic cells in vitiligo that is not encountered in melanoma. Importantly, the cloning of high affinity T cell receptors in retroviral vectors may be suitable for introduction into patient PBL for treatment of malignant melanoma.