Showing papers by "Elodie Segura published in 2016"

Flow Cytometric Analysis of Mononuclear Phagocytes in Nondiseased Human Lung and Lung-Draining Lymph Nodes

Abstract: Rationale: The pulmonary mononuclear phagocyte system is a critical host defense mechanism composed of macrophages, monocytes, monocyte-derived cells, and dendritic cells. However, our current characterization of these cells is limited because it is derived largely from animal studies and analysis of human mononuclear phagocytes from blood and small tissue resections around tumors.Objectives: Phenotypic and morphologic characterization of mononuclear phagocytes that potentially access inhaled antigens in human lungs.Methods: We acquired and analyzed pulmonary mononuclear phagocytes from fully intact nondiseased human lungs (including the major blood vessels and draining lymph nodes) obtained en bloc from 72 individual donors. Differential labeling of hematopoietic cells via intrabronchial and intravenous administration of antibodies within the same lobe was used to identify extravascular tissue-resident mononuclear phagocytes and exclude cells within the vascular lumen. Multiparameter flow cytometry was u...

Review of Mouse and Human Dendritic Cell Subsets.

Abstract: Dendritic cells are specialized antigen-presenting cells that initiate and orient immune responses. Numerous studies in mice and humans have shown that dendritic cells are heterogeneous and comprise several subsets that can be distinguished by their surface phenotype, ontogeny, and molecular signature. This review gives an overview of mouse and human dendritic cell subsets and their defining features and summarizes the current knowledge of dendritic cell subsets' functional specialization in terms of antigen presentation.

CD1c-Related DCs that Express CD207/Langerin, but Are Distinguishable from Langerhans Cells, Are Consistently Present in Human Tonsils

Abstract: Several subsets of dendritic cells (DCs) are present in the oropharyngeal tonsillar tissues and are thought to behave as major actors in development and regulation of immunity by acting as a first line of recognition for airborne and alimentary antigens. We previously discovered in human adult tonsils infected with Epstein-Barr Virus (EBV) a subset of DCs that expressed langerin/CD207, a lectin usually recognized as a hallmark of epidermal Langerhans cells (LCs). In the present study, we analyzed the content of several child and adult tonsils in order to characterize in more detail the phenotype of these tonsillar CD207-expressing DCs (tCD207 DCs) and to compare it with that of other human DC subsets. We showed that all the human tonsils studied (n=12) contained significant proportions of tCD207 DCs among tonsillar cells expressing HLA-DR. Moreover, the presence of tCD207 DCs in tonsils from young children free of EBV infection indicated that these cells could be established early in the tonsil independently of EBV infection. We also showed that tCD207 DCs, that were found mainly located within the tonsillar lymphoid stroma, were distinguishable from LCs by the level of expression of CD1a and EpCAM, and also from human inflammatory DCs (infDCs) by the lack of CD1a, CD206 and CD14 expression. Detailed analysis of cell surface DC markers showed that tCD207 DCs were unrelated to CD141+ DCs or macrophages, but defined a subtype of tonsillar DCs closely related to myeloid resident CD1c DCs. Since it was established that blood CD1c myeloid DCs exhibit plasticity and are capable of expressing CD207 notably in the presence of inflammatory cytokines, it is tempting to speculate that CD207+ CD1c+ DCs may play a specific immune role.

Dendritic Cell Subset Purification from Human Tonsils and Lymph Nodes

Abstract: Dendritic cells (DCs) are a rare population of antigen-presenting cells that initiate immune responses in secondary lymphoid organs. In order to better understand the properties of DC in humans, it is essential to analyze DC subsets directly purified from tissues. Here, we describe a protocol allowing the purification of DC subsets from human tonsils and human lymph nodes.

Cross-Presentation Assay for Human Dendritic Cells.

Abstract: The presentation of exogenous antigens on major histocompatibility complex (MHC) class I molecules, termed cross-presentation, is essential for the initiation of cytotoxic immune responses. Numerous studies in mice and human have shown that dendritic cells are the best cross-presenting cells. The protocol described here allows the assessment of the cross-presentation by human dendritic cells of a model antigen (either soluble or cell associated) to antigen-specific CD8 T cells.