CD2 (LFA-2) is a monomeric surface antigen (MW range 45-58 kDa) of the human T-lymphocyte lineage that is expressed on all peripheral blood T cells. CD2 is one of the earliest T-cell markers, being present on more than 95% of thymocytes and it is also found on some natural killer cells, but not on B lymphocytes. Monoclonal antibodies directed against CD2 inhibit the formation of rosettes with sheep erythrocytes, indicating that CD2 is the erythrocyte receptor or is closely associated with it. The interaction between CD2 and CD58 stabilizes adhesion between T cells and antigen presenting or target cells. Relatively low affinity of CD2 to CD58 (as measured in solution) is compensated within the two-dimensional cell-cell interface to provide tight adhesion. Moreover, T cell activation induces increased CD2 expression and its lateral mobility, making easier contact between CD2 and CD58. Subsequently, T cell activation causes fixation of CD58-CD2 at sites of cell-cell contact, thereby strengthening intercellular adhesion. CD2 deficiency reduces intestinal inflammation and helps to control infection. Diseases associated with CD2 dysfunction include penis squamous cell carcinoma and immune deficiency due to the absence of the thymus.
CD2; Erythrocyte receptor; FLJ46032; LFA-2; LFA-3 receptor; Rosette receptor; T-cell surface antigen CD2; T-cell surface antigen T11/Leu-5