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CD20; B-lymphocyte antigen CD20; membrane-spanning 4-domains subfamily A member 1; B-lymphocyte surface antigen B1; Leu-16; Bp35 (MS4A1)

Function: - CD20 regulates an early step in the initiation of the cell cycle - may be involved in the regulation of B-cell activation & proliferation - may regulate a Ca+2 channel - not shed from the cell surface & does not internalize upon antibody binding - phosphorylated - might be functionally regulated by protein kinase(s) Structure: belongs to the MS4A family Compartment: membrane Expression: - appears on pre B cells after CD19; otherwise similar to CD19 in expression - CD20 is present on pre B & mature B cells but not plasma cells - most B cells (after CD10 & CD19 expression, before CD21/CD22) - mature B cells until plasma cell stage - follicular dendritic cells - small amounts expressed in benign & neoplastic T cells - non-hematopoietic cells, plasma cells & most T cells stain negatively with antibody Pathology: - expressed in: a) B cell lymphoma ~90% b) pre-B ALL/LBL ~40% c) lymphocyte predominant Hodgkin's lymphoma ~80% d) spindle cell thymomas Pharmacology: - rituximab (Rituxan) is a monoclonal antibody which specifically binds CD20 - it is used in treatment of patients with relapsed or refractory, low-grade or follicular, CD20-positive, B-cell non-Hodgkin's lymphoma - britumomab (Zevalin) & bositumomab (Bexxar) are also monoclonal antibodies against CD20

Related

CD3+CD20 Ag in tissue CD19; B-lymphocyte antigen CD19; differentiation antigen CD19; B-lymphocyte surface antigen B4; Leu-12 CD20 Ag in tissue CD20 cells in specimen rituximab (Rituxan, Mabthera, Truxima, Ruxience, Riabni)

General

cluster-of-differentiation antigen; cluster designation antigen; CD antigen phosphoprotein transmembrane 3 protein

Properties

SIZE: entity length = 297 aa MW = 33 kD COMPARTMENT: plasma membrane MOTIF: cytoplasmic domain {1-63} transmembrane domain {64-84} transmembrane domain {85-105} MOTIF: exoplasmic loop {85-84} cytoplasmic loop {106-120} MOTIF: cysteine residue {C111} MODIFICATION: cysteine residue {C220} transmembrane domain {121-141} exoplasmic loop {142-188} transmembrane domain {189-209} cytoplasmic domain {210-297} MOTIF: cysteine residue {C220} MODIFICATION: cysteine residue {C111}

Database Correlations

OMIM 112210 UniProt P11836 Pfam PF04103 Kegg hsa:931

References

  1. Cotran et al Robbins Pathologic Basis of Disease, W.B. Saunders Co, Philadelphia, PA 1989 pg 165
  2. PDR 2000
  3. http://www.pathologyoutlines.com/cdmarkers.html 15 October 2002
  4. Wikipedia; Note: CD20 entry http://en.wikipedia.org/wiki/CD20
  5. UniProt :accession P11836