The thymus contains a diversity of dendritic cells (DCs) that exist in defined locations and have different antigen-processing and -presenting features. This suggests that they play nonredundant roles in mediating thymocyte selection. In an effort to eliminate SIRPα⁺ classic DC2 subsets, we discovered that a substantial proportion expresses the surface lectin, CD301b, in the thymus. These cells resemble the CD301b⁺ type 2 immune response promoting DCs that are present in the skin-draining lymph nodes. Transcriptional and phenotypic comparison to other DC subsets in the thymus revealed that thymic CD301b⁺ cDCs represent an activated state that exhibits enhanced antigen processing and presentation. Furthermore, a CD301b⁺ cDC2 subset demonstrated a type 2 cytokine signature and required steady-state interleukin-4 receptor signaling. Selective ablation of CD301b⁺ cDC2 subsets impaired clonal deletion without affecting regulatory T cells (T_reg cells). The T cell receptor α repertoire sequencing confirmed that a cDC2 subset promotes deletion of conventional T cells with minimal effect on T_reg cell selection. Together, these findings suggest that cytokine-induced activation of DCs in the thymus substantially enforces central tolerance.

胸腺含有多种树突状细胞 (DC)，它们存在于确定的位置并具有不同的抗原加工和呈递特征。这表明它们在介导胸腺细胞选择中发挥非冗余作用。为了消除 SIRPα ⁺经典 DC2 亚群，我们发现很大一部分在胸腺中表达表面凝集素 CD301b。这些细胞类似于促进皮肤引流淋巴结中存在的 DC 的CD301b ^{+ 2 型免疫反应。}与胸腺中其他 DC 亚群的转录和表型比较表明，胸腺 CD301b ⁺ cDC 代表一种激活状态，表现出增强的抗原加工和呈递。此外，CD301b ⁺cDC2 子集表现出 2 型细胞因子特征和需要稳态白细胞介素 4 受体信号传导。CD301b ⁺ cDC2 子集的选择性消融会损害克隆删除而不影响调节性 T 细胞（T _reg细胞）。_{T 细胞受体 α 库测序证实，cDC2 子集促进常规 T 细胞的缺失，而对 T reg}细胞选择的影响最小。总之，这些发现表明，细胞因子诱导的胸腺 DC 激活显着增强了中枢耐受性。