a type III transmembrane protein present on leukocytes, platelets, osteoblasts, and osteoclasts; contributes to the transduction of CD2-generated signals in T cells and natural killer cells; facilitates cytoplasmic calcium flux in B cells, monocytes, and granulocytes; and plays a role in activation of the monocyte oxidative burst; expressed in hemopoietic neoplasms and myelomas.
