Sachamitr Patty, Leishman Alison J, Davies Timothy J, Fairchild Paul J
Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom.
Front Immunol. 2018 Jan 8;8:1935. doi: 10.3389/fimmu.2017.01935. eCollection 2017.
The advent of induced pluripotent stem cells (iPSCs) has begun to revolutionize cell therapy by providing a convenient source of rare cell types not normally available from patients in sufficient numbers for therapeutic purposes. In particular, the development of protocols for the differentiation of populations of leukocytes as diverse as naïve T cells, macrophages, and natural killer cells provides opportunities for their scale-up and quality control prior to administration. One population of leukocytes whose therapeutic potential has yet to be explored is the subset of conventional dendritic cells (DCs) defined by their surface expression of CD141. While these cells stimulate cytotoxic T cells in response to inflammation through the cross-presentation of viral and tumor-associated antigens in an MHC class I-restricted manner, under steady-state conditions CD141 DCs resident in interstitial tissues are focused on the maintenance of homeostasis through the induction of tolerance to local antigens. Here, we describe protocols for the directed differentiation of human iPSCs into a mixed population of CD11c DCs through the spontaneous formation of embryoid bodies and exposure to a cocktail of growth factors, the scheduled withdrawal of which serves to guide the process of differentiation. Furthermore, we describe the enrichment of DCs expressing CD141 through depletion of CD1c cells, thereby obtaining a population of "untouched" DCs unaffected by cross-linking of surface CD141. The resulting cells display characteristic phagocytic and endocytic capacity and acquire an immunostimulatory phenotype following exposure to inflammatory cytokines and toll-like receptor agonists. Nevertheless, under steady-state conditions, these cells share some of the tolerogenic properties of tissue-resident CD141 DCs, which may be further reinforced by exposure to a range of pharmacological agents including interleukin-10, rapamycin, dexamethasone, and 1α,25-dihydoxyvitamin D. Our protocols therefore provide access to a novel source of DCs analogous to the CD141 subset under steady-state conditions and may, therefore, find utility in the treatment of a range of disease states requiring the establishment of immunological tolerance.
诱导多能干细胞（iPSC）的出现已开始彻底改变细胞疗法，它为获取通常无法从患者身上获得足够数量用于治疗目的的稀有细胞类型提供了便利来源。特别是，针对多种白细胞群体（如初始T细胞、巨噬细胞和自然杀伤细胞）的分化方案的开发，为它们在给药前的扩大培养和质量控制提供了机会。一类治疗潜力尚未得到探索的白细胞群体是由CD141表面表达所定义的传统树突状细胞（DC）亚群。虽然这些细胞在炎症反应中通过以MHC I类限制性方式交叉呈递病毒和肿瘤相关抗原刺激细胞毒性T细胞，但在稳态条件下，驻留在间质组织中的CD141 DC主要通过诱导对局部抗原的耐受性来维持体内平衡。在此，我们描述了通过胚状体的自发形成和暴露于生长因子混合物，将人iPSC定向分化为CD11c DC混合群体的方案，生长因子混合物的定时撤出用于引导分化过程。此外，我们描述了通过去除CD1c细胞来富集表达CD141的DC，从而获得不受表面CD141交联影响的“未受干扰”DC群体。所得细胞表现出特征性的吞噬和内吞能力，并在暴露于炎性细胞因子和Toll样受体激动剂后获得免疫刺激表型。然而，在稳态条件下这些细胞具有组织驻留CD141 DC的一些致耐受性特性，通过暴露于包括白细胞介素-10、雷帕霉素、地塞米松和1α,25-二羟基维生素D在内的一系列药物制剂，这些特性可能会进一步增强。因此，我们的方案提供了一种类似于稳态条件下CD141亚群的新型DC来源，因此可能在治疗一系列需要建立免疫耐受性的疾病状态中发挥作用。
