Immunoregulatory receptor which inhibits the T-cell response (PubMed:21383057, PubMed:24743150, PubMed:25267631). May promote differentiation of embryonic stem cells, by inhibiting BMP4 signaling (PubMed:20042595). May stimulate MMP14-mediated MMP2 activation (By similarity). Expressed in spleen, thymus, bone marrow, lymph node, and in T-cells within the lamina propria of the small intestine (PubMed:21768399). Detected on CD4+ and CD8+ T-cells, bone marrow-derived dendritic cells (BMDCs), peritoneal macrophages, neutrophils, and natural killer (NK) cells (PubMed:21768399). In spleen and lymph nodes, highly expressed on CD4+ T-cell populations, and at lower levels on CD8+ T-cells (PubMed:21383057). In thymus, has low expression on CD4+ cells and CD8+ cells, and not detected on CD4+CD8+ cells (PubMed:21383057). Expressed in splenic and peritoneal CD11b cells (PubMed:21383057). Not detected in most B cells and NK cells (at protein level) (PubMed:21383057). Also detected at lower levels in non-hematopoeitic tissues such as heart, brain, lung, kidney, muscle, ovary, and testis (PubMed:21768399, PubMed:21383057). Detected in 7-day and 17-day embryos. Up-regulated by phorbol 12-myristate 13-acetate (PMA) and the cytokine IFNG. At the cell surface, may be cleaved by MMP14. N-glycosylated. Viable and fertile (PubMed:24743150, PubMed:25267631). At birth, lymphocyte populations in bone marrow, spleen and lymph nodes appear to be normal (PubMed:24743150, PubMed:25267631). Frequencies of activated peripheral T-cells are increased in older animals (PubMed:24743150, PubMed:25267631). Levels of the inflammatory cytokines CCL11, CXCL10, CCL2 and CXCL9 are significantly increased (PubMed:25267631). Tissues show signs of chronic inflammation, however this does not progress to overt autoimmune disease (PubMed:25267631). Extended N-terminus.