Purity: > 95% by SDS - PAGE Format: Liquid. In Phosphate Buffered Saline (pH 7.4) containing 10% glycerol.. CD81, also known as CD81 antigen isoform 1, belongs to the tetraspanin family. It interacts directly with immunoglobulin superfamily member 8 (IGSF8, CD316) and CD36. In B cells, it is part of a complex with CD21, CD19 and Leu13. This complex reduces the threshold for B cell activation through B cell receptors by linking Ag specific recognition and CD21 mediator recognition. On T cells it associates with CD4 and CD8 and provides a costimulatory signal with CD3. Recombinant human CD81, fused to hIgG-His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.