CD8⁺ T cells bearing residency markers are abundant within airway epithelium and appear to migrate to medLN via lymphatics. (A) Localization of antigen-specific CD8⁺ T cells in the lungs of mice infected 18 d earlier with influenza virus revealed abundant CD103⁺ Ly6C^lo cells within and surrounding Epcam1⁺ airway epithelium. (B) Characterization of blood vessels (BV), lymphatic vessels (LV), and airway epithelium (AW) in the lungs of influenza-immune mice. Blood vessels typically costained with CD31 and Lyve1, while lymphatic vessels stained solely with Lyve1. Arrow highlights an antigen-specific CD8⁺ T cell within the lumen compartment of the lymphatic vessel. (C) Lymphatic vessels were commonly found abutting airway epithelium (also observed in B). Arrow highlights an antigen-specific CD103⁺ CD8⁺ T cell traversing the lymphatic endothelium. Regions of airway epithelium contacting Lyve1⁺ lymphatic vessels were often sparse for antigen-specific CD8⁺ T cells. (D) Representative IF microscopy of the medLN of a mouse infected 18 d earlier with PR8-ova. Note antigen-specific CD103⁺ Ly6C^lo CD8⁺ T cells potentially infiltrating medLN through regions of the LN associated with afferent lymphatics and colocalizing with Lyve1 staining. Numbers orient regions of the medLN enlarged below. Antigen-specific cell staining was removed from the right duplicate images to better display the CD103⁺ Ly6C^lo phenotype. Scale bars represent 50 µm (A–C) or 200 µm (D). Representative images are from at least three sections per tissue, per mouse, of three or more individual mice.