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T细胞受体（h3T）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。结果，h3TA2小鼠在青春期发生快速、对称和进行性的表皮色素脱色，循环小鼠T细胞对色素细胞（包括人类HLA-A2+黑色素细胞和黑色素瘤细胞）的细胞毒性与CD4或CD8的表达无关。这个模型非常适合设计干扰对黑素细胞的持续免疫反应的方法。在目前的提议中需要验证的假设是，在积极脱色小鼠中，鼓励调节性T细胞反应，同时干扰炎症性Th17的贡献，可以阻止白癜风的进展。初步数据显示，对预防自身免疫反应很重要的调节性T细胞，实际上在人类白癜风患者的皮肤中是缺乏的。同样，在小鼠模型中，在活性脱色小鼠的循环中检测到Treg数量减少。目前的第一个目标是进一步表征和优化新的小鼠模型，参考CD4+ T细胞亚群的发育和丰度和调节反应，并通过将h3TA2模型与k14启动子下SCF表达导致表皮黑色素细胞表达的小鼠杂交，进一步“人源化”模型。接下来，研究人员提出通过过继转移可追踪的FoxP3-EGFP+ Treg，并通过创造有利的细胞因子环境，主要在tgf - β增加和IL-6浓度降低的情况下，推动幼稚T细胞向调节性表型和功能发展，从而增加脱色素小鼠中Treg的丰度，这将在培养和小鼠模型中得到解决。在第三个也是最后一个目标下，调节性T细胞将通过过度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）被重定向到皮肤，以便在发生色素脱失的地方有利于免疫抑制。

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.