Purity: Greater than 90%, as determined by SDS-PAGE. Aggregation: Less than 10%, as determined by HPLC. Filtration: 0.2 μm post-manufacturing filtered. CD48 (Blast-1) belongs to the CD2 subset of the Ig superfamily that includes CD2, CD2F-10, CD58, CD84, CD150, CD229, CD244 and others. These molecules bind to the same or another members of the Ig family, thus mediating 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. Further, signaling through CD48 results in eosinophil activation and CD48 expression is increased in several infectious diseases. CD48 is strongly expressed on lymphocytes and monocytes, weakly on granulocytes but is absent on platelets, fibroblasts, epithelium and endothelium. CD48 is one of marker for detecting the defects of GPI anchoring structure on the patients with paroxysmal nocturnal hemoglobulinuria (PNH) and serves as a low affinity ligand for CD2. 2B4-CD48 interaction may be involved in the pathology of allergic airway diseases and provide a pharmacological target for the treatment of diseases such as allergic rhinitis and asthma.