CD5 (N-Term) Rabbit Monoclonal Antibody (Clone RM354)

CD5 is a type I transmembrane glycoprotein receptor and member of the scavenger receptor cysteine-rich (SRCR) superfamily.¹ It is composed of three extracellular cysteine-rich domains, a transmembrane region, and a cytoplasmic tail containing an imperfect immunoreceptor tyrosine-based activating motif (ITAM). CD5 is expressed at differing levels on mature CD4⁺ and CD8⁺ T cells and thymocytes, and at lower levels on B1a cells and B cell chronic lymphocytic leukemia (B-CLL) cells.² It acts a negative regulator of T cell signaling, despite the presence of an ITAM, and has a role in promoting the survival of thymocytes and mature T cells. CD5⁺ B cells are at their highest levels during development, lowest during early adulthood, and increase in middle-to-late adulthood, a change that correlates with an increased incidence of B-CLL and mantle cell lymphoma (MCL).³ CD5⁺ B cells primarily have a follicular mantle phenotype and produce low affinity polyreactive antibodies. CD5 expression on T cells protects against experimental autoimmune encephalomyelitis (EAE) in mice, but the levels of CD5⁺ B cells are increased in patients with systemic lupus erythematosus (SLE).^4,5 CD5 has a complex role in cancer, with high levels of CD5 on tumor-infiltrating T cells (TILs) protecting TILs from apoptosis, but reduced CD5 levels on TILs enhancing CD8⁺ T cell-mediated lysing of malignant cells.⁴ CD5 has commonly been used as a marker of T cells, B1a cells, and B-CLL cells.² Cayman’s CD5 (N-Term) Rabbit Monoclonal Antibody (Clone RM354) can be used for immunohistochemistry (IHC) and Western blot (WB) applications.

WARNING This product is not for human or veterinary use.

1. Perez-Villar, J.J., Whitney, G.S., Bowen, M.A., et al. CD5 negatively regulates the T-cell antigen receptor signal transduction pathway: Involvement of SH2-containing phosphotyrosine phosphatase SHP-1. Mol. Cell. Biol. 19(4), 2903-2912 (1999).

2. Burgueño-Bucio, E., Mier-Aguilar, C.A., and Soldevila, G. The multiple faces of CD5. J. Leukoc. Biol. 105(5), 891-904 (2019).

3. Dono, M., Cerruti, G., and Zupo, S. The CD5⁺ B-cell. Int. J. Biochem. Cell Biol. 36(11), 2105-2111 (2004).

4. Dalloul, A. CD5: A safeguard against autoimmunity and a shield for cancer cells. Autoimmun. Rev. 8(4), 349-353 (2009).

5. Pers, J.-O., Jamin, C., Predine-Hug, F., et al. The role of CD5-expressing B cells in health and disease (review). Int. J. Mol. Med. 3(3), 239-245 (1999).