Human CD81 is a member of the tetraspan family of leukocyte cell surface molecules which are involved in signal transduction, cell-cell adhesion, and cellular activation (1). Association of CD81 with integrins appears to be functionally important in the regulation of cell adhesion and activation (2, 3). Work with CD81-null mice indicates CD81 is important for development of humoral immune response (4). The level of cell surface CD81 decreases rapidly upon activation of T or B cell, and appears to be shed off in exosomes (6). CD81 colocalizes with intracellular HIV-1 containing vesicals (5) and interacts with Gag viral assembly protiens(7).
Isotype: Murine IgG1
Immunogen: Human B cell line from Burkitt lymphoma
Specificity: Antibody 18.104.22.168 reacts with the 24 kd tetraspan CD81 molecule (1). The binding site of this mAb interferes with the binding of Hepatiatis C E2 glycoprotein to CD81 and may involve Leu162 (8).
1. Leukocyte Typing V (S.F. Schlossman, et al, eds.) Oxford University Press, Oxford (1995) p. 684-691.
2. B.A. Mannion, et al, (1996) J Immunol 157: 2039-2047.
3. S.C. Todd, et al, (1996) J Exp Med 184: 2055-2060.
4. H.T. Maecker & S. Levy, (1997) J Exp Med 185: 1505-1510.
5. H. Koppensteiner, M. Schuler, et al. (2012) J Virol 86(5): 2826-2836.
6. B. Fritzsching, M. Ott, et al. (2002) J Immunol 169(10): 5531-5537.
7. B Grigorov, D. Muriaux, et al. (2009) Retrovirol 6: 28.
8. H.E. Drummer, K.A. Wilson, P. Poumbourios (2002) J Virol 76(21): 11143-11147. PMID: 12368358