分子别名（Synonym）
MS4A1,CD20,MS4A-1
表达区间及表达系统（Source）
Human CD20 Full Length, His Tag, HEK293 (CD0-H52H3) is expressed from human 293 cells (HEK293). It contains AA Met 1 - Pro 297 (Accession # P11836-1).
Predicted N-terminus: Met 1
蛋白结构（Molecular Characterization）
This protein carries a polyhistidine tag at the C-terminus.
The protein has a calculated MW of 35.2 kDa. The protein migrates as 40 kDa under reducing (R) condition (SDS-PAGE) due to glycosylation.
内毒素（Endotoxin）
Less than 1.0 EU per μg by the LAL method.
纯度（Purity）
>90% as determined by SDS-PAGE.
制剂（Formulation）
Delivered as bulk protein in a 0.2 μm filtered solution of 50 mM HEPES, 150 mM NaCl, DDM, CHS, pH 7.5 with glycerol as protectant.
Contact us for customized product form or formulation.
运输（Shipping）
This product is supplied as sterile liquid solution and shipped frozen with dry ice.
存储（Storage）
Please avoid repeated freeze-thaw cycles.
This product is stable after storage at:
- The product MUST be stored at -70°C or lower upon receipt;
- -70°C for 3 months under sterile conditions.
电泳（SDS-PAGE）
Human CD20 Full Length, His Tag, HEK293 on SDS-PAGE under reducing (R) condition. The gel was stained overnight with Coomassie Blue. The purity of the protein is greater than 90%.
活性（Bioactivity）-ELISA
Immobilized Rituximab at 2 μg/mL (100 μL/well) can bind Human CD20 Full Length, His Tag, HEK293 (Cat. No. CD0-H52H3) with a linear range of 2-16 ng/mL (in presence of DDM and CHS) (QC tested).
Protocol
Immobilized Ofatumumab at 2 μg/mL (100 μL/well) can bind Human CD20 Full Length, His Tag, HEK293 (Cat. No. CD0-H52H3) with a linear range of 1-20 ng/mL (in presence of DDM and CHS) (QC tested).
Protocol
活性（Bioactivity）-SPR
MabThera® (Rituximab) captured on CM5 chip via Anti-human IgG Fc antibodies surface can bind Human CD20 Full Length, His Tag, HEK293 (Cat. No. CD0-H52H3) with an affinity constant of 1.77 nM as determined in a SPR assay (in presence of DDM and CHS) (Biacore T200) (Routinely tested).
Protocol
Ofatumumab (Human IgG1) captured on CM5 chip via Anti-human IgG Fc antibodies surface can bind Human CD20 Full Length, His Tag, HEK293 (Cat. No. CD0-H52H3) with an affinity constant of 3.57 nM as determined in a SPR assay (in presence of DDM and CHS) (Biacore T200) (Routinely tested).
Protocol
活性（Bioactivity）-BLI
Loaded MabThera® (Rituximab) on ProteinA Biosensor, can bind Human CD20 Full Length, His Tag, HEK293 (Cat. No. CD0-H52H3) with an affinity constant of 8.1 nM as determined in BLI assay (ForteBio Octet Red96e) (Routinely tested).
Protocol
背景（Background）
B-lymphocyte antigen CD20 is also known as B-lymphocyte surface antigen B1, Leukocyte surface antigen Leu-16, Membrane-spanning 4-domains subfamily A member 1 and MS4A1, is an activated-glycosylated phosphoprotein expressed on the surface of all B-cells beginning at the pro-B phase (CD45R+, CD117+) and progressively increasing in concentration until maturity. CD20 is expressed on all stages of B cell development except the first and last; it is present from late pro-B cells through memory cells, but not on either early pro-B cells or plasma blasts and plasma cells. It is found on B-cell lymphomas, hairy cell leukemia, B-cell chronic lymphocytic leukemia, and melanoma cancer stem cells. The protein has no known natural ligand and its function is to enable optimal B-cell immune response, specifically against T-independent antigens. It is suspected that it acts as a calcium channel in the cell membrane. CD20 / MS4A1 is the target of the monoclonal antibodies (mAb) rituximab, Ibritumomab tiuxetan, and tositumomab, which are all active agents in the treatment of all B cell lymphomas and leukemias. Defects in CD20 / MS4A1 are the cause of immunodeficiency common variable type 5 (CVID5); also called antibody deficiency due to CD20 defect. CVID5 is a primary immunodeficiency characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen.
