– CD5: a type I transmembrane protein found on T cells, thymocytes, and some B cells that is a ligand for CD72 and is involved in cellular activation or adhesion; expressed in B-cell chronic lymphocytic leukemia and T-cell lymphoma. CD5 Protein, Human, Recombinant (hFc & Avi) is expressed in HEK293 mammalian cells with C-hFc-Avi tag. The predicted molecular weight is 67.1 kDa and the accession number is P06127.