Integrin subunit alpha E (ITGAE) (ITGAE)

Integrin subunit alpha E (ITGAE), commonly known as CD103, is a transmembrane protein that pairs with the integrin beta 7 subunit to form the alphaEbeta7 heterodimer. This receptor is a hallmark marker for tissue-resident memory T cells (Trm) and is highly expressed on a specific subset of CD8+ tumor-infiltrating lymphocytes (TILs) within the tumor microenvironment (Source: UniProt P38570, PMID: 30104354). The primary biological function of ITGAE is to mediate the adhesion of lymphocytes to epithelial cells by binding to E-cadherin, which facilitates the retention and positioning of T cells within epithelial tissues and solid tumors. In oncology, the presence of CD103+ CD8+ TILs is strongly associated with improved clinical outcomes and enhanced sensitivity to immune checkpoint inhibitors, as these cells exhibit high cytotoxic potential and rapid effector function (Source: PMID: 28923825). While ITGAE is targeted by inhibitory antibodies like etrolizumab to treat inflammatory bowel disease by reducing pathological lymphocyte trafficking, in cancer research, it is primarily utilized as a biomarker for identifying potent anti-tumor T cell populations. Strategies to enhance the recruitment and retention of ITGAE-expressing TILs are currently a major focus in the development of next-generation cancer immunotherapies (Source: PMID: 31611615).

Other names

CD103Integrin alpha-EHML-1 antigenIntegrin alpha-IEL

Etrolizumab is a humanized monoclonal antibody that binds to the beta7 subunit of the heterodimeric integrins alpha4beta7 and alphaEbeta7 (ITGAE/ITGB7), thereby blocking their interaction with the ligands MAdCAM-1 and E-cadherin, respectively (Source: PMID: 24851862).