Intestinal Lamina Propria TcRγδ + Lymphocytes Selectively Express IL-10 and IL-17

■ Abstract Background: The characteristics and roles of gut lymphocytes have been only partly elucidated, in particular with regard to activation patterns. Objectives: To characterize lymphocytes from various parts of the gut and examine their activation pattern as a network. Methods: Lymphocytes were isolated from the epithelium, the lamina propria, Peyer's patches, mesenteric lymph nodes, the spleen, and peripheral blood of naive mice. They were then characterized for T cell phenotype, T cell receptors (TcRs), activation markers, and cytokine production. Results: The results showed a gradient of cells with an increasing proportion of TcRγδ + , CD8αα + cells towards the gut lumen, with the highest number found in intraepithelial lymphocytes. These cells, together with lamina propria lymphocytes (LPLs) were also characterized by a memory-like phenotype (CD25 – CD45RB low and CD44 high ) and CD69 expression. CD8+ TcRγδ + LPLs produced IL-10 and IL-17, while TcRαs + LPLs were FoxP3 positive.