CD2, also known as leukocyte function-associated antigen-2 (LFA-2), is a member of the immunoglobulin superfamily of cell adhesion molecules.1 It is expressed on the surface of >95% of thymocytes, and essentially all B cells, T cells and NK cells.1-3 In the mouse, CD2 is the receptor for CD48.4 CD2 is thought to play a major role in mediating T-cell adhesion, T-cell recognition/activation, Tcell signaling and intrathymic differentiation.5-10