Modulating tolerance in a spontaneous mouse model of autoimmune vitiligo

描述(申请人提供)：通过将人T细胞受体与人酪氨酸酶(H3T)相结合，结合相关的人类人类HLA-A*0201分子的转基因表达，建立了一种新的自发的自身免疫性白癜风小鼠模型。由此产生的h3TA2小鼠在青春期出现快速、对称和渐进性的毛皮脱色，循环中的小鼠T细胞对色素细胞(包括人类HLA-A2+黑素细胞和黑色素瘤细胞)的细胞毒性不依赖于CD4或CD8的表达。这种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。在目前的方案中要检验的假设是，在积极脱色的小鼠中，鼓励调节性T细胞反应，同时干扰炎症Th17的贡献，可以阻止白癜风的进展。初步数据显示，人类白癜风患者皮肤中几乎缺乏调节性T细胞，这对防止自身免疫反应非常重要。同样，在小鼠模型中，在活跃脱色的小鼠的循环中可以检测到数量减少的Treg。当前建议的第一个目标是参考CD4+T细胞亚群和调节反应的发展和丰富，并通过将h3TA2模型杂交到由于K14启动子下SCF表达而在表皮表达黑素细胞的小鼠，进一步使该模型人性化，从而进一步表征和优化新的小鼠模型。接下来，有人建议通过过继转移可追踪的FoxP3-EGFP+Treg来增加脱色小鼠的Treg的丰度，并通过创造良好的细胞因子环境来推动幼稚T细胞向调节表型和功能的方向发展，主要是在增加转化生长因子-β和降低IL-6浓度的情况下，这将在培养和小鼠模型中解决。在第三个也是最终目标中，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)而重定向到皮肤，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.