Heterogeneity and Imprinting of Long-lived Plasma Cells

特异性血清抗体和自身抗体滴度的长期半衰期不同是明显的，浆细胞（PC）库可以适应新的特异性，同时保持既定的记忆。尽管出现了异质PC亚群的证据和临床相关性，但在骨髓（BM）中，PC亚群动力学水平上抗体滴度的调节与稳定性的关系仍不清楚。我们在这里假设BMPC的亚群与不同的抗体无关的功能有关，并通过潜在的不同调控确保了长期存在的PC池的同时稳定性和适应性。质粒细胞分析技术建立了人类骨髓PC （BMPC）的表型多样性，为研究人类骨髓PC亚群的差异组成和动态提供了必要的依据。重要的是，初步分析揭示了新的CD19-CD56+和CD19-CD45- PC亚群作为正常人BMPC库（称为非规范PC， ncPC）的一部分。IgG+ PC在NcPC中富集，表明系统B细胞活化产生的PC被选择到NcPC池中。与PC表达已知的CD19+CD45+CD56-表型相反，ncPC表达编码转录因子FOXP2和TCF-1、生长因子DKK-1的mRNA，并上调编码Wnt家族成员、Wnt受体和信号分子的几个基因，表明Wnt网络在ncPC生物学中有选择性地发挥作用。在体外，DKK-1增强了人基质细胞中PC存活因子APRIL、IL-6和CXCL12的表达，表明Wnt通路调节了ncPC与环境的特权串扰。在这个项目中，我们将进一步在体外表征新的非典型PC亚群，并以T细胞依赖和独立的方式研究它们在体外的诱导作用，以解决ncPC命运在B细胞激活水平上由组织T辅助细胞特异性因子印记的假设。我们将分析ncPC与其他PC亚群的相互关系，如典型CD19+CD45+CD56- BMPC，作为选择性治疗PC亚群的基础。我们将进一步阐明BMPC中CD45和CD56表达差异对其存活和组织定位的功能影响。该项目将描述FOXP2、TCF-1、DKK-1、Wnt信号和Wnt配体表达在人类ncPC中与抗体无关的人类PC功能的作用。

Different long-term half-lives of specific serum antibody and autoantibody titers are evident, and the plasma cell (PC) repertoire can accommodate new specificities while maintaining established memory. Despite emerging evidence and clinical relevance of heterogenous PC subsets, the regulation of antibody titers at the level of PC subset dynamics vs. stability in the bone marrow (BM) remains unclear. We here hypothesize that subsets of BMPC are linked to distinct antibody-independent functions, and by underlying different regulation ensure the concurrent stability and adaptation of the long-lived PC pool.PC profiling by mass cytometry established a profound phenotypical diversity of human bone marrow PC (BMPC), providing us with the necessary grounds to study differential composition and dynamics of human PC subsets. Importantly, preliminary analyses disclosed novel, CD19-CD56+ and CD19-CD45- PC subsets as parts of the normal human BMPC pool (termed non-canonical PC, ncPC). NcPC were enriched for IgG+ PC, indicating selection of PC emerging from systemic B cell activation into the pool of ncPC. In contrast to PC expressing the known CD19+CD45+CD56- phenotype, ncPC expressed mRNA encoding the transcription factors FOXP2 and TCF-1, the growth factor DKK-1, and upregulated several genes encoding members of the Wnt family, Wnt receptor and signaling molecules, suggesting a role of the Wnt network selectively in the biology of ncPC. In vitro, DKK-1 enhanced expression of PC survival factors APRIL, IL-6 and CXCL12 in human stromal cells, suggesting that Wnt pathway modulation mediates a privileged crosstalk of ncPC with their environment. In this project, we will further characterize novel non-canonical PC subsets ex vivo, and study their induction in vitro in T cell-dependent and -independent manner to address the hypothesis that ncPC fate is imprinted by tissue T helper cell specific factors at the level of B cell activation. We will analyze the interrelation of ncPC with other PC subsets, such as canonical CD19+CD45+CD56- BMPC, as a basis for selective therapeutic targeting of PC subsets. We will further elucidate the functional consequences of differential CD45 and CD56 expression by BMPC for their survival and tissue localization. The project will delineate the role of FOXP2, TCF-1, DKK-1, Wnt signaling and Wnt ligand expression in human ncPC in the context of antibody-independent functions of human PC.