CD19

CD19, also known as B4 or CVID3, is a membrane immunoglobulin that is expressed on follicular dendritic cells and B cells. It contains two Ig-like C2-type domains in the extracellular portion while the cytoplasmic portion undergoes phosphorylation upon the recipient of different cellular signals. CD19 is involved in the B cell response to antigens. It is a low-affinity antigen receptor that is crucial for the decreasing of the threshold for antigen receptor-dependent stimulation. CD19 is often associated with CD21, CD81, CD82, VAVA2, and Complement receptor 2 for its biological function. Defects in CD19 are the main cause of immunodeficiency common variable type 3 (CVID3), or antibody deficiency, a disorder that is characterized by poor B-cell differentiation and impaired antibody production.

CD19 is a biomarker for B-cell lymphomas. It is now under evaluation as a target for antibody-based immunotherapies against B-cell lymphomas as well as some autoimmune diseases.

Entrez Gene ID: 930
UniProt ID: P15391