CD11c, a member of the integrin family, is a transmembrane protein that pairs with CD18 (β2 integrin) to form the heterodimeric receptor CR4 (αXβ2). Primarily expressed on dendritic cells (DCs), macrophages, natural killer (NK) cells, and certain T-cell subsets, CD11c serves as a key surface marker for identifying myeloid-derived immune cells, particularly conventional DCs. Its discovery in the 1980s stemmed from monoclonal antibody development targeting leukocyte differentiation antigens, which revealed its role in cell adhesion, migration, and immune signaling.
Functionally, CD11c facilitates pathogen recognition, phagocytosis, and immune cell trafficking by binding ligands like fibrinogen and ICAM-1. It also participates in antigen presentation and T-cell activation via immunological synapse formation. In research, CD11c antibodies (e.g., clone HL3 in mice) are widely used in flow cytometry to isolate DCs and monitor immune responses. Immunohistochemistry applications leverage these antibodies to map DC distribution in tissues during infection, cancer, or autoimmune diseases.
Therapeutically, CD11c-targeting strategies are explored for modulating DC activity in autoimmune disorders (e.g., lupus) or enhancing vaccine efficacy. However, its broad expression across myeloid lineages necessitates careful specificity assessment in experimental or clinical contexts. Recent studies also implicate CD11c in tumor microenvironment regulation, highlighting its dual roles in pro- and anti-inflammatory processes.