CD48 (Blast-1) belongs to the CD2 subset of the Ig superfamily, which includes CD2, CD2F-10, CD58, CD84, CD150, CD229, CD244 and others. These molecules bind to the same or another members of their family, thus mediate homotypic or heterotypic adhesion. CD48 is a GPI-anchored protein broadly expressed on hematopoietic cells and serves as a high affinity ligand for 2B4 and low affinity ligand for CD2. 2B4-CD48 interaction among NK cells and NK-T cells regulates cell proliferation. Signaling through CD48 results in eosinophil activation and CD48 expression is increased in several infectious diseases.