T-cell surface antigen CD2 is also known as Erythrocyte receptor, LFA-2, LFA-3 receptor, Rosette receptor, T-cell surface antigen T11/Leu-5. It is a protein that in humans is encoded by the CD2 gene. It is a single-pass type I membrane protein. contains 1 Ig-like C2-type domain and 1 Ig-like V-type domain. T-cell surface antigen CD2 interacts with lymphocyte function-associated antigen (LFA-3) and CD48/BCM1 to mediate adhesion between T-cells and other cell types. It is implicated in the triggering of T-cells, the cytoplasmic domain is implicated in the signaling function.