Functional analyses of dendritic subsets in immune regulation

在这个项目中，我们研究了功能差异的内吞传统的树突状细胞（DC）与I型干扰素生产浆细胞样preDC（P-preDC）在免疫调节方面的细胞因子的生产，T细胞活化，和调节性T细胞的扩增。1）Ly 49 Q是Ly 49家族的成员，其在Gr-1^+细胞上表达，但不在NK和NKT细胞上表达。发现常规DCs对Ly 49 Q是阴性的，而骨髓来源的DCs在低水平表达并且被IFN上调。另一方面，Ly 49 Q在外周淋巴组织中表达于CD 11 c ^+B220^+Gr-1^+P-preDCs上。然而，P-preDCs在骨髓中的表达水平是可变的。这是由于P-preDCs分化阶段的差异，因为Ly 49 Q在培养时自发表达，而Ly 49 Q ^+P-preDCs通过CpG-ODN产生更大量的IFN-α/β、IL-6和IL-12。2）已知CD 25 ^+ CD 4 ^+调节性或抑制性T细胞（Tcells，Tcells）能够维持免疫自身耐受，防止自身免疫。以前，我们已经表明，当APC是抗原负载的成熟树突状细胞（DC）时，TCFs增殖并保留其抗原依赖性抑制功能。使用同种异体多克隆TCLs，DC被证明有效地维持Foxp 3在TCLs中的表达，并且在IL-2存在下对于同种异体抗原特异性TCLs的扩增是有效的。此外，那些扩增的TTRs有效抑制由⑶ 25-⑶ 4- T细胞诱导的GvHD。3）我们产生了在Langerin基因座中具有灵长类DTR的靶向插入的小鼠。在注射DT后24 h内，在成年Langerin-DTR小鼠中有效地和选择性地消融LC。表皮LC室在稳定状态下的重建需要至少4周。LC-耗竭小鼠的功能分析显示，真皮DC能够介导皮肤CHS反应。

In this project, we examined functional differences of endocytoic conventional dendritic cells (DCs) with type I interferon-producing plasmacyotoid preDCs (P-preDCs) in immune regulations in terms of cytokine production, T cell activation, and expansion of regulatory T cells. The following results were obtained.1)Ly49Q is a member of the Ly49 family that is expressed on Gr-1^+ cells, but not on NK and NKT cells. Conventional DCs were found to be negative for Ly49Q, while bone marrow-derived DCs expressed at low level and upregulated by IFN. On the other hand, Ly49Q was expressed on CD11c^+B220^+Gr-1^+P-preDCs in peripheral lymphoid tissues. However, the expression level on P-preDCs were variable in bone marrow. This was ascribed to the difference in differentiation stage of P-preDCs, since Ly49Q was expressed spontaneously upon culture and Ly49Q^+P-preDCs produced larger amounts of IFN-α/β,IL-6 and IL-12 by CpG-ODN.2)CD25^+CD4^+ regulatory or suppressor Tcells (Tregs) is known to maintain immunological self-tolerance, preventing autoimmunity. Previously we have shown that Tregs proliferate and retain their antigen-dependent suppressive functions when the APCs are antigen-loaded mature dendritic cells (DCs). Using allogeneic polyclonal Tregs, DCs were demonstrated to effectively sustain expression of Foxp3 in Tregs and to be potent for the expansion of alloantigen-specific Tregs in the presence of IL-2. Moreover, those expanded Tregs were efficient to suppressed GvHD induced by CD25- CD4- T cells.3)We generated mice that harbor a targeted insertion of a primate DTR in the Langerin locus. LCs were effectively and selectively ablated in adult Langerin-DTR mice within 24 h after injection of DT. Reconstitution of the epidermal LC compartment in the steady state took at least 4 wk. Functional analysis of LC-depleted mice revealed that dermal DCs were able to mediate a cutaneous CHS response.