CD20expressing

CD20expressing refers to cells that display the CD20 antigen on their surface, most notably mature B lymphocytes. The CD20 protein is a membrane-spanning glycoprotein encoded by the MS4A1 gene and is expressed on most pre-B and mature B cells, but not on hematopoietic stem cells or terminally differentiated plasma cells. As such, CD20expressing cells serve as both a B-cell marker and a therapeutic target.

CD20 is a four-pass transmembrane protein whose precise function is not completely understood. It is believed to participate in regulation of calcium signaling and B-cell activation. Although not strictly required for B-cell development, CD20expressing cells are widely used to identify B cells in flow cytometry and immunohistochemistry and serve as practical targets for antibody-based strategies.

CD20expression can be variable in certain B-cell malignancies, and plasma cells typically lack CD20. Detection methods include flow cytometry on peripheral blood or bone marrow samples and immunohistochemistry on tissue sections, often as part of diagnostic workups to establish B-cell lineage and tumor burden.

Clinical relevance centers on anti-CD20 monoclonal antibodies that deplete CD20expressing B cells. Rituximab is the most established example, with subsequent antibodies such as ofatumumab and obinutuzumab. These therapies are used for various B-cell cancers and some autoimmune diseases, and may be combined with chemotherapy or radiolabeled approaches. Adverse effects include infusion reactions and increased infection risk.

See also: MS4A1, cluster of differentiation, rituximab.