CD103
See also ITGAE.
Integrin, alpha E (ITGAE) also known as CD103 (Cluster of Differentiation 103) is an integrin.
CD103 binds integrin beta 7 (β7– ITGB7) to form the complete heterodimeric integrin molecule αEβ7, which has no distinct name.
The αEβ7 complex is often referred to as "CD103" though this appellation strictly refers only to the αE chain. Note that the β7 subunit can bind with other integrin α chains, such as α4 (CD49d).
Tissue Distribution
CD103 is expressed widely on intraepithelial lymphocyte (IEL) T cells (both αβ T cells and γδ T cells) and on some peripheral regulatory T cells (Tregs). It has also been reported on lamina propria T cells.
Function
The chief ligand for αEβ7 is E-cadherin, an adhesion molecule (CAM) found on epithelial cells. It is probably important for T cell homing to the intestinal sites.
Tregs are important for decreasing the immune response and appear to play a crucial role in the prevention of autoimmune diseases. Tregs are defined as CD4+/CD25+/Foxp3+ cells.
Some CD4+/FoxP3- cells also express CD103 and have been attributed regulatory activity. It is unclear whether the presence of CD103 on Treg cells represents a specialized feature for Treg, or Treg differentiation of IEL T cells.
References
Kilshaw PJ, Higgins JM (2002). "Alpha E: no more rejection?". J. Exp. Med. 196 (7): 873–5. doi:10.1084/jem.20021404. PMID #12370249#.
Lehmann J, Huehn J, de la Rosa M, Maszyna F, Kretschmer U, Krenn V, Brunner M, Scheffold A, Hamann A (October 2002). "Expression of the integrin alpha Ebeta 7 identifies unique subsets of CD25+ as well as CD25- regulatory T cells". Proc. Natl. Acad. Sci. U.S.A. 99 (20): 13031–6. PMID# 12242333#.
Aziz S, Fackler OT, Meyerhans A, Müller-Lantzsch N, Zeitz M, Schneider T (January 2005). "Replication of M-tropic HIV-1 in activated human intestinal lamina propria lymphocytes is the main reason for increased virus load in the intestinal mucosa". J. Acquir. Immune Defic. Syndr. 38 (1): 23–30. doi:10.1097/00126334-200501010-00005. PMID #15608520#.
Hadley GA, Bartlett ST, Via CS, Rostapshova EA, Moainie S (October 1997). "The epithelial cell-specific integrin, CD103 (alpha E integrin), defines a novel subset of alloreactive CD8+ CTL". J. Immunol. 159 (8): 3748–56. PMID #9378961#.
Agace WW, Higgins JM, Sadasivan B, Brenner MB, Parker CM (October 2000). "T-lymphocyte-epithelial-cell interactions: integrin alpha(E)(CD103)beta(7), LEEP-CAM and chemokines". Curr. Opin. Cell Biol. 12 (5): 563–8. doi:10.1016/S0955-0674(00)00132-0. PMID #10978890#.
Allakhverdi Z, Fitzpatrick D, Boisvert A, Baba N, Bouguermouh S, Sarfati M, Delespesse G (December 2006). "Expression of CD103 identifies human regulatory T-cell subsets". J. Allergy Clin. Immunol. 118 (6): 1342–9. doi:10.1016/j.jaci.2006.07.034. PMID #17137867#.