Recombinant Human CD19 Fc Chimera Avi-tag Protein, CF

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Recombinant Human CD19 Fc Chimera Avi-tag Protein Binding Activity
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Recombinant Human CD19 Fc Chimera Avi-tag Protein, CF Summary

Why choose R&D Systems Avi-tag CD19 Protein?

  • Guaranteed Bioactivity and High Purity: Bioactivity tested by functional ELISA and purity determined by SDS-PAGE to be greater than 95%.
  • Lot-to-Lot Consistency: Stringent QC testing performed on each lot to ensure consistent activity and purity.
  • Bulk Quantities Available: Bulk up and save with large mass quantities to meet your research needs. Supply agreements available, partner with us. Please contact us.
  • Most Respected, Most Cited Brand in Proteins: With over 35 years of providing the best recombinant proteins to the scientific community, R&D Systems continues to lead the industry in quality, activity, and purity.

Find the full range of Avi-tag and amine biotinylated proteins Avi-tag Proteins

Product Specifications

>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Level
<0.10 EU per 1 μg of the protein by the LAL method.
Measured by its binding ability in a functional ELISA. When Human CD19 Antibody (FMC63) (Novus Biologicals, Catalog # NBP2-52716) is immobilized at 0.5 µg/mL (100 µL/well), it binds to Biotinylated Recombinant Human CD19 Fc Chimera Avi-tag (Catalog # AVI9269) with an ED50 of 7.5-45 ng/mL.
Chinese Hamster Ovary cell line, CHO-derived human CD19 protein
Human CD19
Accession # P15391
Accession #
N-terminal Sequence
Structure / Form
Disulfide-linked homodimer, biotinylated via Avi-tag
Predicted Molecular Mass
59 kDa
75-95 kDa, under reducing conditions

Product Datasheets

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Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.


Formulation Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose.
Reconstitution Reconstitute at 500 μg/mL in PBS.
Shipping The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.

Scientific Data

Binding Activity Recombinant Human CD19 Fc Chimera Avi-tag Protein Binding Activity View Larger

When Human CD19 antibody (FMC63) (Novus Biologicals Catalog # NBP2-52716) is immobilized at 0.5 μg/mL, 100 μL/well, Recombinant Human CD19 Fc Chimera Avi-tag (Catalog # AVI9269) binds with an ED50 of 7.5-45 ng/mL.

SDS-PAGE Recombinant Human CD19 Fc Chimera Avi-tag Protein SDS-PAGE View Larger

2 μg/lane of Recombinant Human CD19 Fc Chimera Avi-tag (Catalog # AVI9269) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 75-95 kDa and 150-190 kDa, respectively.

Reconstitution Calculator

Reconstitution Calculator

The reconstitution calculator allows you to quickly calculate the volume of a reagent to reconstitute your vial. Simply enter the mass of reagent and the target concentration and the calculator will determine the rest.


Background: CD19

CD19, also known as B4, is a transmembrane glycoprotein of the immunoglobulin superfamily that plays a central role in B cell activation and humoral immune responses (1, 2). CD19 consists of an extracellular domain (ECD) with two C2-type Ig-like domains, a transmembrane segment, and a cytoplasmic domain with nine tyrosine residues, 3 of which are critical for function (1, 2). Within the mature ECD, human CD19 shares 57% amino acid sequence identity with mouse and rat CD19. CD19 is expressed throughout B cell development from pre‑B cells through mature B cells, and it is commonly used as a B cell lineage marker (1, 2). It is required for the responsiveness of mature B cell to antigen stimulation, germinal center development, and antibody affinity maturation (1, 2). CD19 associates with the B cell antigen receptor (BCR), CD81, CD38, CD21, CD22, and IFITM1/CD225/Leu-13 (1, 3). These associations enable CD19 to amplify B cell signaling and reduce the threshold for antigen stimulation through the BCR (1, 3). CD19 polymorphisms and up-regulation can lead to the development of autoimmunity by promoting autoantibody production (2). CD19 has emerged as promising therapeutic target for hematologic cancers and solid tumors, such as leukemias and lymphomas (4, 5). Immunotherapy using a chimeric antigen receptor (CAR) targeting CD19 has emerged as promising therapeutic target for hematologic cancers and solid tumors, such as leukemias and lymphomas (4, 5). The first CD19 CAR T cell therapies have been granted FDA approval for the treatment of B cell malignancies with several more in clinical trials (6). Our Avi-tag Biotinylated TGF-beta 1 features biotinylation at a single site contained within the Avi-tag, a unique 15 amino acid peptide. Protein orientation will be uniform when bound to streptavidin-coated surface due to the precise control of biotinylation and the rest of the protein is unchanged so there is no interference in the protein's bioactivity.

  1. Wang, K. et al. (2012) Exp. Hematol. Oncol. 1:36.
  2. Del Nargo, C.J. et al. (2005) Immunol. Res. 31:229.
  3. Yu, F. et al. (2010) J. Neurooncol. 103:187.
  4. Kochenderfer, J. et al. (2015) J Clin. Oncol. 33:540.
  5. Lee, D. et al. (2015) Lancet. 385:517.
  6. Ahmad, A. et al. (2020) Int. J. Mol. Sci. 21:3906.
Entrez Gene IDs
930 (Human); 12478 (Mouse); 365367 (Rat); 397669 (Porcine); 607898 (Canine); 102145514 (Cynomolgus Monkey); 100147468 (Equine)
Alternate Names
B4; B-lymphocyte antigen CD19; B-lymphocyte surface antigen B4; CD19 antigen; CD19 molecule; CD19; CVID3; Differentiation antigen CD19; Leu-12; MGC12802; T-cell surface antigen Leu-12


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