Modulates T-cell-mediated immune responses and the development of acute and chronic transplant rejection. May play a positive regulatory role in bone formation and has a dual role in the bone-immune interface. Induces antitumor immunity as it activates both acquired and innate immunity leading to natural killer cell and CD8 T-cell dependent killing of tumor cells (By similarity). Interacts with TREML2 and this interaction enhances T-cell activation. Belongs to the immunoglobulin superfamily. BTN/MOG family.