CD103

CD103
Identifiers
Symbol	?
HGNC	6149
OMIM	192974
RefSeq	NM_002208
UniProt	P38570
Search for Structures Swiss-model Domains InterPro

CD103, also known as Integrin alpha E (ITGAE), is a protein that in humans is encoded by the ITGAE gene. CD103 is a type I transmembrane glycoprotein that belongs to the integrin family of cell surface receptors. It is primarily expressed on a subset of T lymphocytes, particularly tissue-resident memory T cells, and plays a crucial role in the immune system by mediating cell adhesion and signaling.

Structure

CD103 is an integrin alpha chain that pairs with the beta chain β7 to form the αEβ7 integrin complex. This complex is involved in the adhesion of lymphocytes to epithelial cells, particularly in the gut and other mucosal tissues. The extracellular domain of CD103 binds to E-cadherin, a cell adhesion molecule expressed on epithelial cells, facilitating the retention of lymphocytes in epithelial tissues.

Function

CD103 is primarily expressed on T cells, including regulatory T cells (Tregs) and tissue-resident memory T cells (Trm). It plays a significant role in the immune surveillance of epithelial tissues by promoting the retention and localization of T cells in these areas. This is particularly important in the gut, where CD103+ T cells contribute to the maintenance of mucosal immunity and tolerance.

The interaction between CD103 and E-cadherin is crucial for the homing and retention of T cells in epithelial tissues. This interaction also influences T cell activation and differentiation, contributing to the immune response against pathogens while maintaining tolerance to self-antigens.

Clinical Significance

CD103 expression is used as a marker to identify tissue-resident memory T cells, which are important for long-term immunity and protection against reinfection. These cells are characterized by their ability to remain in non-lymphoid tissues and provide rapid immune responses upon re-exposure to pathogens.

In the context of cancer, CD103+ T cells have been associated with improved prognosis in certain types of tumors, such as colorectal cancer, due to their ability to mediate anti-tumor immunity. Additionally, CD103 is used as a marker in the diagnosis of certain hematological malignancies, such as hairy cell leukemia, where it is expressed on the surface of the malignant B cells.

Research Directions

Ongoing research is focused on understanding the role of CD103 in various immune-mediated diseases and its potential as a therapeutic target. Studies are exploring how modulation of CD103 expression or function could enhance immune responses in cancer or promote tolerance in autoimmune diseases.

Also see

• Integrin
• E-cadherin
• T cell
• Tissue-resident memory T cell
• Regulatory T cell
• Hairy cell leukemia