CD19 is a single-pass type I transmembrane protein belonging to the immunoglobulin (Ig) superfamily (IgSF).  It contains two Ig-like C2-type domains.  CD19 is an important pan B cell marker and co-stimulatory protein involved in growth regulation of B cells. CD19 is expressed only in B cells and follicular dendritic cells of the hematopoietic system. It is present on most pre-B cells and most non-T-cell acute lymphocytic leukemia cells (ALL) and B-cell type chronic lymphocytic leukemia cells (CLL).  CD19 is a co-receptor for the antigen receptor complex on B cells to decrease the threshold for antigen receptor-dependent stimulation. It forms a complex with CD21, CD81 and CD225 in the membrane of B cells. It associates with GRB2 and SOS when activated and phosphorylated on Tyr-348 / Tyr-378. CD19 is a hallmark differentiation antigen of the B cell lineage and positively regulates antigen B-cell receptor (BCR) signal transduction for B cell selection, maturation, and differentiation.  Defects in CD19 are the cause of immunodeficiency common variable type 3 (CVID3), which is characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen. The defect results from a failure of B-cell differentiation and impaired secretion of antibody while the numbers of circulating B cells is usually in the normal range, but can be low.

CD19 is a single-pass type I transmembrane protein belonging to the immunoglobulin (Ig) superfamily (IgSF).  It contains two Ig-like C2-type domains.  CD19 is an important pan B cell marker and co-stimulatory protein involved in growth regulation of B cells. CD19 is expressed only in B cells and follicular dendritic cells of the hematopoietic system. It is present on most pre-B cells and most non-T-cell acute lymphocytic leukemia cells (ALL) and B-cell type chronic lymphocytic leukemia cells (CLL).  CD19 is a co-receptor for the antigen receptor complex on B cells to decrease the threshold for antigen receptor-dependent stimulation. It forms a complex with CD21, CD81 and CD225 in the membrane of B cells. It associates with GRB2 and SOS when activated and phosphorylated on Tyr-348 / Tyr-378. CD19 is a hallmark differentiation antigen of the B cell lineage and positively regulates antigen B-cell receptor (BCR) signal transduction for B cell selection, maturation, and differentiation.  Defects in CD19 are the cause of immunodeficiency common variable type 3 (CVID3), which is characterized by antibody deficiency, hypogammaglobulinemia, recurrent bacterial infections and an inability to mount an antibody response to antigen. The defect results from a failure of B-cell differentiation and impaired secretion of antibody while the numbers of circulating B cells is usually in the normal range, but can be low.

 

Product Details

 

Gene Symbol: CD19; B4; CVID3; Leu-12

 

NCBI Gene ID: 930

 

Uniprot Entry: P15391

 

Construct Details: Expressed as the combination of a heavy chain (HC) containing VH from anti-CD19 mAb and CH1-3 region of mouse IgG2a  and a light chain (LC) encoding VL from anti-CD19 mAb and CL of mouse kappa light chain.  Exists as a disulfide linked dimer of the HC and LC hetero-dimer under non-reducing condition.

 

Source: Mammalian cells stably expressing anti-CD19 heavy chain and light chain and growing in chemical-defined media with no animal components. 

 

M.W.: Calculated molecular mass (kDa): 146 (49 kDa for a single HC, 24 kDa for a single LC); Estimated by SDS-PAGE under non-reducing condition(kDa): 150

 

Purity: >95% judged by SDS-PAGE under reducing condition (see the gel image above, labeled as DTT "+")

 

Formulation: Supplied at 0.5 mg/ml in sterile PBS pH7.4 without any carrier protein or preservative (the concentration determined by UV absorption with an A280nm of 1.0 for 0.73 mg/ml of IgG and verified by SDS-PAGE and Coomassie blue staining)

 

Endotoxin Level: <0.1 EU per 1 μg of purified recombinant protein determined by the LAL method

 

Biological Activity: Binds CD19 extracellular domain proteins (SKU#FCL0806 & SKU#FCL0803) with high affinity  (K_D < 1 nM) measured by ELISA with immobilized CD19 protein @100 ng/well (see the attached Technical Data).  Recognizes cell surface CD19 by flow cytometry, IHC staining and fluorescent microscopy.  Binds CD19 with the same specificity as anti-CD19 monocloncal antibodies, human IgG1 (SKU#MAB0776) and rabbit IgG (SKU#MAB0803)

 

  

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

Restriction: This product is not transferable or re-sellable.  Customer obtain no right to transfer, assign, or sublicense its use rights, or to transfer, resell, package, or otherwise distribute the product, or to use the product for the benefit of any third party or for any commercial purpose.  Customer may only use the product in compliance with applicable local, state and federal laws, regulations and rules.  Customer may not directly or indirectly use the product or allow the transfer, transmission, export or re-export of all or any part of the product in violation of any export control law or regulation of the united states or any other relevant jurisdiction.  Your use of this product constitutes acceptance of the terms of this limited use agreement.  Please refer to our “terms & conditions” for details.  If you are not willing to accept the limitation of this agreement, G&P Biosciences will accept return of the product for a full/partial refund.

 

 

Technical Data

 

Recombinant CD19 ECD protein (SKU#FCL0806) was immobilized at 100 ng/well on a 96-well ELISA plate and incubated with serially diluted anti-CD19 human IgG1 monoclonal antibody (SKU#MAB0776). Anti-CD22 (SKU#MAB1175) human IgG1 monoclonal antibody was used as a control to demonstrate the specificity of CD19 binding under the experimental conditions.  The bound antibodies were detected by goat anti-human IgG HRP-conjugated secondary antibody.  The ELISA binding curve was fit and K_D was calculated for anti-CD19 : CD19 binding (affinity/avidity) to be 181 ± 16 pM. 

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

 

Storage

 

The product is shipped at 4°C. Upon receipt, centrifuge the product briefly before opening the vial. It is recommended to store small aliquots at the temperature below –20°C for long-term storage and the product is stable for 3 months. The undiluted protein can be stored at 4°C for no more than 2 weeks.

 

 

Use a manual defrost freezer and avoid repeated freeze-thaw cycles.

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

 

References

 

1. J. Exp. Med. 168:1205-1210 (1988)

2. J. Immunol. 143:712-717 (1989)

3.  J Immunol. 158:4662-9 (1997).

4. Leuk Lymphoma. 43:613-6 (2002)

5. N. Engl. J. Med. 354:1901-1912 (2006)

 

 

Documentation

 

Product datasheet (pdf) can be downloaded here: MAB0806-PDS.pdf

 

 

 

Additional supporting documents, including COA and MSDS are available upon request.

 

 

 

FOR RESEARCH USE ONLY. NOT FOR DIAGNOSTIC OR THERAPEUTIC USE IN HUMAN.

Restriction: This product is not transferable or re-sellable.  Customer obtain no right to transfer, assign, or sublicense its use rights, or to transfer, resell, package, or otherwise distribute the product, or to use the product for the benefit of any third party or for any commercial purpose.  Customer may only use the product in compliance with applicable local, state and federal laws, regulations and rules.  Customer may not directly or indirectly use the product or allow the transfer, transmission, export or re-export of all or any part of the product in violation of any export control law or regulation of the united states or any other relevant jurisdiction.  Your use of this product constitutes acceptance of the terms of this limited use agreement.  Please refer to our “terms & conditions” for details.  If you are not willing to accept the limitation of this agreement, G&P Biosciences will accept return of the product for a full/partial refund.