Project description:Palatine tonsils are secondary lymphoid organs that are strategically positioned in the oropharynx to secure a first line of defense against oral pathogens. Specialized immune-interacting fibroblasts, generally termed fibroblastic reticular cells (FRC), underpin distinct microenvironments within lymphoid organs to compartmentalize and direct the efficient interaction and activation of immune cells. As a particular anatomical property, palatine tonsils harbor a reticular-shaped lymphoepithelium that generates an antigen sampling zone in the crypts. While the histological ultrastructure and the immune cell composition of human palatine tonsils has been elaborated in detail, the molecular identity of the diverse stromal cell compartments including FRC and the specialized lymphoepithelium remains largely unknown. Here, we have employed single cell transcriptomics and extensive flow cytometric analyses to unveil the molecular identity of tonsillar cells and to disentangle the heterogeneity of fibroblast and epithelial cell subsets in palatine tonsils. Our results reveal a remarkable conservation of stromal cell organization and molecularly-defined subsets in infant and adult human palatine tonsils.
Project description:GEP on Affymetrix U133+2.0 microarrays was performed on 6 centroblasts and 6 paired centrocytes from human tonsils in order to explore CB/CC transition and GC-B cell specific signatures
Project description:Non-hematopoietic lymph node stromal cells (LNSCs) regulate lymphocyte trafficking, survival, and function for key roles in host defense, autoimmunity, alloimmunity, and lymphoproliferative disorders. However, study of LNSCs in human diseases is complicated by a dependence on viable lymphoid tissues, which are most often excised prior to establishment of a specific diagnosis. Here, we demonstrate that cryopreservation can be used to bank lymphoid tissue for the study of LNSCs in human disease. Using human tonsils, lymphoid tissue fragments were cryopreserved for subsequent enzymatic digestion and recovery of viable non-hematopoietic cells. Flow cytometry and single-cell transcriptomics identified comparable proportions of LNSC cell types in fresh and cryopreserved tissue. Moreover, cryopreservation had little effect on transcriptional profiles, which showed significant overlap between tonsils and lymph nodes. The presence and spatial distribution of transcriptionally defined cell types was confirmed by in situ analyses. Our broadly applicable approach promises to greatly enable research into the roles of LNSC in human disease.