Identification of Conventional Dendritic Cell Subpopulations in Conducting Airway Mucosa

Dendritic cells belong to a heterogenic population of innate immune cells distributed across the tissues. These cells are considered to be potential therapeutic targets due to their ability to sense exogenous antigens and self-tissue damage. In the lungs, two subpopulations of conventional dendritic cells, cDC1 and cDC2, were identified. Distinguishing the populations is commonly performed by flow cytometry based on the different expressions of transcription factors and surface markers. Thus, after the exclusion of precursors and the cells rather than dendritic cells, G protein-coupled receptor XCR1 and membrane glycoprotein SIRPA (CD172a) are used to characterize cDC1 as XCR1^hiCD172a^lo and cDC2 as XCR1^loCD172a^hi. Analysis by flow cytometry permits the accurate identification of the subpopulations; however, to define the precise location of cDC1 and cDC2 in relation to the structural tissue cells, confocal laser scanning microscopy (CLSM) is required. Together with the advantage of spatial cell distribution identification, CLSM has two limitations compared to flow cytometry. The former is the limited number of antibodies that can be simultaneously applied. Besides, not all the antibodies suitable for cell staining and flow cytometry show stable antigen recognition during the tissue staining and CLSM. In this study, we applied anti-XCR1 and anti-CD172a to visualize cDC1 and cDC2 in conducting airway mucosa of mice. We detect the distribution of these cells in a steady state and upon the airway inflammation.