Modulating tolerance in a spontaneous mouse model of autoimmune vitiligo

描述（由申请人提供）：通过将人酪氨酸酶的人T细胞受体（h3 T）引入小鼠，结合相关人HLA-A*0201分子的转基因表达，建立了一种新的自发性自身免疫性白癜风小鼠模型。所得到的h3 TA 2小鼠在青春期期间发生快速、对称和进行性的皮毛脱色，并且循环小鼠T细胞对色素细胞（包括人HLA-A2+黑素细胞和黑素瘤细胞）的细胞毒性不依赖于CD 4或CD 8表达。该模型非常适合设计干扰对黑素细胞的持续免疫应答的方法。在目前的建议中要测试的假设是，鼓励调节性T细胞反应，同时干扰主动脱色小鼠中炎症性Th 17的贡献，可以阻止白癜风的进展。初步数据显示，人类白癜风患者的皮肤中几乎缺乏对预防自身免疫反应很重要的调节性T细胞。同样，在小鼠模型中，在主动脱色小鼠的循环中可检测到Treg数量减少。本提案的第一个目的是进一步表征和优化新的小鼠模型，参考CD 4 + T细胞亚群和调节反应的发育和丰度，并通过将h3 TA 2模型与在表皮中表达黑素细胞的小鼠杂交来进一步“人源化”该模型，所述黑素细胞是在k14启动子下SCF表达的结果。接下来，提出通过过继转移可追踪的FoxP 3-EGFP+ Treg，并通过主要在增加的TGF-β和降低的IL-6浓度下产生有利的细胞因子环境来驱动幼稚T细胞向调节表型和功能的发育，来增加脱色小鼠中Treg的丰度，这将在培养物和小鼠模型中解决。在第三个和最后一个目标下，调节性T细胞将通过过表达相关的皮肤归巢受体（包括但不限于CCR-8和CLA和/或趋化因子如CCL-1）而被重定向到皮肤，以便有利于发生脱色的免疫抑制。 公共卫生相关性：题为“调节自身免疫性白癜风自发小鼠模型中的耐受性”的项目通过提高Treg浓度并支持其皮肤归巢特性，同时在新生成的小鼠模型中干扰炎性Th 17，解决了白癜风中缺乏调节性T细胞反应的问题，该模型包括与HLA-A2背景下识别的酪氨酸酶肽反应的人转基因T细胞受体：h3 T-A2小鼠

DESCRIPTION (provided by applicant): A new, spontaneous mouse model for autoimmune vitiligo has been created by introducing a human T cell receptor to human tyrosinase (h3T) into mice, combined with transgenic expression of the associated human HLA-A*0201 molecule. Resulting h3TA2 mice develop rapid, symmetrical and progressive depigmentation of the pelage during adolescence, and cytotoxicity of circulating mouse T cells towards pigment cells, including human HLA-A2+ melanocytes and melanoma cells, is independent of CD4 or CD8 expression. This model is very suited to devise means of interfering with an ongoing immune response to melanocytes. The hypothesis to be tested within the current proposal is that encouraging a regulatory T cell response while interfering with a contribution for inflammatory Th17 in actively depigmenting mice can halt the progression of vitiligo. Preliminary data show that regulatory T cells, important to prevent autoimmune responses, are virtually lacking from the skin of human vitiligo patients. Likewise, in the mouse model, a reduced number of Treg was detectable in the circulation of actively depigmenting mice. The first objective of the current proposal is to further characterize and optimize the new mouse model with reference to the development and abundance of CD4+ T cell subsets and regulatory responses, and by further 'humanizing' the model by crossbreeding the h3TA2 model to mice that express melanocytes in the epidermis as a consequence of SCF expression under the k14 promotor. Next it is proposed to increase the abundance of Treg in depigmenting mice by adoptive transfer of traceable FoxP3-EGFP+ Treg, and by driving the development of naive T cells towards a regulatory phenotype and function by creating a favorable cytokine environment primarily under increased TGF-beta and reduced IL-6 concentrations, which will be addressed both in culture, and within the mouse model. Under the 3rd and final aim, regulatory T cells will be redirected towards the skin by overexpressing relevant skin homing receptors including but not limited to CCR-8 and CLA and/or chemokines such as CCL-1, in order to favor immune inhibition there where depigmentation is taking place. PUBLIC HEALTH RELEVANCE: The project entitled 'modulating tolerance in a spontaneous mouse model of autoimmune vitiligo' addresses the lack of a regulatory T cell response in vitiligo by elevating Treg concentrations and supporting their skin homing properties while interfering with inflammatory Th17 within a newly generated mouse model that encompasses a human transgenic T cell receptor reactive with a tyrosinase peptide recognized in the context of HLA-A2: the h3T-A2 mouse.