title: Human Lung Dendritic Cells: Spatial Distribution and Phenotypic Identification in Endobronchial Biopsies Using Immunohistochemistry and Flow Cytometry.
abstract: The lungs are constantly exposed to the external environment, which in addition to harmless particles, also contains pathogens, allergens, and toxins. In order to maintain tolerance or to induce an immune response, the immune system must appropriately handle inhaled antigens. Lung dendritic cells (DCs) are essential in maintaining a delicate balance to initiate immunity when required without causing collateral damage to the lungs due to an exaggerated inflammatory response. While there is a detailed understanding of the phenotype and function of immune cells such as DCs in human blood, the knowledge of these cells in less accessible tissues, such as the lungs, is much more limited, since studies of human lung tissue samples, especially from healthy individuals, are scarce. This work presents a strategy to generate detailed spatial and phenotypic characterization of lung tissue resident DCs in healthy humans that undergo a bronchoscopy for the sampling of endobronchial biopsies. Several small biopsies can be collected from each individual and can be subsequently embedded for ultrafine sectioning or enzymatically digested for advanced flow cytometric analysis. The outlined protocols have been optimized to yield maximum information from small tissue samples that, under steady-state conditions, contain only a low frequency of DCs. While the present work focuses on DCs, the methods described can directly be expanded to include other (immune) cells of interest found in mucosal lung tissue. Furthermore, the protocols are also directly applicable to samples obtained from patients suffering from pulmonary diseases where bronchoscopy is part of establishing the diagnosis, such as chronic obstructive pulmonary disease (COPD), sarcoidosis, or lung cancer.
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet.
authors.forename: Faezzah
authors.initials: F
authors.lastname: Baharom
authors.affiliation: Division of Medicine, Department of Public Health and Clinical Medicine, Umeå University.
authors.forename: Gregory
authors.initials: G
authors.lastname: Rankin
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet.
authors.forename: Saskia
authors.initials: S
authors.lastname: Scholz
authors.affiliation: Division of Medicine, Department of Public Health and Clinical Medicine, Umeå University.
authors.forename: Jamshid
authors.initials: J
authors.lastname: Pourazar
authors.affiliation: Divison of Infectious Diseases, Department of Clinical Microbiology, Umeå University.
authors.forename: Clas
authors.initials: C
authors.lastname: Ahlm
authors.affiliation: Division of Medicine, Department of Public Health and Clinical Medicine, Umeå University.
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet; Anna.Smed.Sorensen@ki.se.
authors.forename: Anna
authors.initials: A
authors.lastname: Smed-Sörensen
mesh_terms: D001706:Biopsy; D001999:Bronchoscopy; D003713:Dendritic Cells / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping / Q000379:methods*; D008168:Lung / Q000166:cytology* / Q000276:immunology