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

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 naïve 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– CD45RBlow and CD44high) and CD69 expression. CD8+ TcRγδ+ LPLs produced IL-10 and IL-17, while TcRαß+ LPLs were FoxP3 positive. Conclusions: Gut lymphocytes express various receptors and cytokines according to their location. These specifi c features suggest a differential function for gut lymphocytes depending on their location.