May act as receptor (By similarity). Negatively regulates TCR-mediated CD4(+) T cell proliferation and activation, possibly by binding an unknown ligand on the T cell surface . Enhances Toll-like receptor-mediated production of pro-inflammatory cytokines by macrophages and neutrophils (By similarity).
Subcellular locations: Cell membrane
Expressed in fetal and adult liver, lung, testis, thymus and spleen. Expressed in blood neutrophils.