Arginase-I is expressed by ckit+IL-7Ra+ populations in cryptopatches (166.11)

Abstract

Abstract Arginase-I is expressed by alternatively activated macrophages during type-2 inflammation and is strongly induced by the cytokines IL-4 and IL-13. In order to track arginase-I expression, our lab developed a YFP-arginase-I (Yarg) reporter mouse. In the naive Yarg mouse, we detected arginase-I-expressing cells that were CD45+ckit+IL-7Ra+, but lacked the common myeloid and lymphoid cell surface markers CD11b, CD11c, Gr-1, B220, CD3, and NK1.1. In the small intestine, these cells were found in cryptopatches and expressed RORγt and LTβ RNA, consistent with a lymphoid tissue inducer (LTI) phenotype. Indeed, we found Yarg+RORγt+ cells that were present in adult and one-day-old neonatal mouse small intestine. Interestingly, we also identified Yarg+RORγt- cells that were located in cryptopatches and were still present in the lamina propria of RORγt-deficient mice. These ckit+IL-7Ra+ subsets were the primary Yarg+CD45+ cells in several organs. Thus, ckit+IL-7Ra+ cells are a previously unappreciated arginase-I-expressing population in naive mice.