CD7 is a 40 kDa transmembrane, single-chain glycoprotein, which is a member of the immunoglobulin superfamily. CD7 is expressed by the majority of thymocytes and mature T cells, NK cells and pre-B cells. It plays an essential role in T-cell interactions and also in T-cell/B-cell interaction during early lymphoid development. The function of CD7 is not yet known although cross-linking of CD7 with induces a T cell transmembrane calcium flux and CD7 expression is induced by ionomycin. The CD7 molecule has been reported to be the receptor for the IgM-Fc portion (FcR mu) on the surface of T cells.
