CD20 explained
CD20 is a non-glycosylated phosphoprotein expressed on the surface of all mature B-cells.
Membrane-spanning 4-domains, subfamily A, member 1, also known as MS4A1, is a human gene.[1]
Function
The protein has no known natural ligand[2] and its function is unclear. It is suspected that it acts as a calcium channel in the cell membrane.
Expression
CD20 is expressed on all stages of B cell development except the first and last; it is present from pre-pre B cells through memory cells, but not on either pro-B cells or plasma cells.[3]
It is found on B-cell lymphomas, hairy cell leukemia, and B-cell chronic lymphocytic leukemia. It is also found on skin/melanoma cancer stem cells.[4]
Clinical significance
It is the target of the monoclonal antibodies rituximab, Ibritumomab tiuxetan, and tositumomab, which are all active agents in the treatment of all B cell lymphomas and leukemias. Additional antibody therapeutics under development (phase II or III clinical trials) include AME-133v (Applied Molecular Evolution), Ocrelizumab (Roche), Ofatumumab (Genmab), TRU-015 (Trubion) and IMMU-106 (Immunomedics).[5]
FMC7 appears to be a conformational variant.[6]
External links
- representations of the shape are found here and more detail here
Notes and References
- Web site: Entrez Gene: MS4A1 membrane-spanning 4-domains, subfamily A, member 1.
- The biology of CD20 and its potential as a target for mAb therapy.http://www.ncbi.nlm.nih.gov/sites/entrez?Db=PubMed&TermToSearch=15564720
- Book: Bona, Constantin. Francisco A. Bonilla. Martin Soohoo. Textbook of Immunology. 2. 1996. CRC Press. 9783718605965. 5. 102.
- Fang D, Nguyen TK, Leishear K, et al. A tumorigenic subpopulation with stem cell properties in melanomas. Cancer Res.. 65. 20. 9328–37. 2005. 16230395. 10.1158/0008-5472.CAN-05-1343.
- Note: information included in this article only found in table present in print version of article. News: K. John Morrow Jr. Methods for Maximizing Antibody Yields. Genetic Engineering & Biotechnology News. Mary Ann Liebert, Inc.. 36. 2008-06-15. 2008-07-06.
- Polyak MJ, Ayer LM, Szczepek AJ, Deans JP. A cholesterol-dependent CD20 epitope detected by the FMC7 antibody. Leukemia. 17. 7. 1384–9. 2003. 12835728. 10.1038/sj.leu.2402978.
