CD103 is a marker for alloantigen-induced regulatory CD8+ T cells. J Immunol.

CD103 / cluster of differentiation 103, also known as Integrin, alpha E (ITGAE), is an integrin protein that in human is encoded by the ITGAE gene. CD103 binds integrin beta 7 (β7– ITGB7) to form the complete heterodimeric integrin molecule αEβ7, which has no distinct name.

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.

CD103+CD11b+ lamina propria DCs express low amounts of the macrophage markers CD172a, F4/80 and CX3CR1 and low Csf-1R. In contrast, lamina propria CD103− CD11b+ cells express the macrophage markers CD172a, F4/80, CX3CR1, and the Csf-1R.

CD11b is expressed on the surface of many leukocytes including monocytes, neutrophils, natural killer cells, granulocytes and macrophages, as well as on 8% of spleen cells and 44% of bone marrow cells. Functionally, CD11b regulates leukocyte adhesion and migration to mediate the inflammatory response.

Integrins regulate cellular growth, proliferation, migration, signaling, and cytokine activation and release and thereby play important roles in cell proliferation and migration, apoptosis, tissue repair, as well as in all processes critical to inflammation, infection, and angiogenesis.

CD11c is a type I transmembrane protein that is expressed on monocytes, granulocytes, a subset of B cells, dendritic cells, and macrophages and may be demonstrated on B-cell chronic lymphocytic leukemia, marginal zone lymphomas, and hairy cell leukemia. CD11c is abundantly expressed in monocytes and macrophages.

Monocytes that circulate in the bloodstream also express F4/80 on the surface, but the level is lower than on tissue macrophages, indicating another correlation between the level of F4/80 and the adhesion properties of the corresponding mononuclear blood cell (Gordon and Austyn, 1981).

CD19 and B220 (CD45R), an isoform of CD45, are surface markers of mature, resting B cells. CD45 is a tyrosine phosphatase that participates in the modulation of the immune response in both B and T cells. It is present on immature and mature B cells, but it is lost upon differentiation into plasma cells (1–3).

CD11b is considered a pan-myeloid marker (expressed after granulocyte-monocyte progenitors (GMP) phase in the bone marrow). CD11c is a prefered marker for dendritic cells. But there is exceptions given the variety of tissue distribution of myeloid cells.

Integrins also function as signal transducers, activating various intracellular signaling pathways when activated by matrix binding. Integrins and conventional signaling receptors often cooperate to promote cell growth, cell survival, and cell proliferation.

As integrins lack enzymatic activity, signaling is instead induced by the assembly of signaling complexes on the cytoplasmic face of the plasma membrane.