Role of mast cells and basophils in the development of atopic dermatitis

在Th2中，嗜碱性细胞和树突状细胞对外源抗原暴露的相对贡献尚不清楚。在这里，我们报告了嗜碱性粒细胞在不同抗原的表皮致敏时诱导Th2极化的能力，使用嗜碱性粒细胞条件耗尽的Bas TRECK转基因小鼠。在体内，嗜碱性细胞负责Th2向半抗原和肽抗原倾斜，而不是向蛋白质抗原倾斜。与此一致的是，嗜碱性细胞不能大量摄取或加工卵清蛋白蛋白，而是通过主要组织相容性复合体II类将卵清蛋白肽提供给T细胞进行Th2分化。有趣的是，在树突状细胞存在的情况下，嗜碱性细胞在卵清蛋白暴露时促进Th2偏斜。综上所述，我们的研究结果表明，嗜碱性细胞单独能够诱导Th2与半抗原和肽抗原的偏斜，但需要树突状细胞在表皮免疫时诱导Th2与蛋白抗原的偏斜。

The relative contributions of basophils and dendritic cells in Th2 skewing to foreign antigen exposure remain unclear. Here we report the ability of basophils to induce Th2 polarization upon epicutaneous sensitization with different antigens using basophil conditionally depleted Bas TRECK transgenic mice. Basophils are responsible for Th2 skewing to haptens and peptide antigens, but not protein antigens in vivo. Consistent with this, basophils cannot take up or process ovalbumin protein in significant quantities, but present ovalbumin peptide to T cells for Th2 differentiation via major histocompatibility complex class II. Intriguingly, basophils promote Th2 skewing upon ovalbumin protein exposure in the presence of dendritic cells. Taken together, our results suggest that basophils alone are able to induce Th2 skewing with haptens and peptide antigens but require dendritic cells for the induction of Th2 for protein antigens upon epicutaneous immunization.