CD19 Proteins

CD19 is a type I transmembrane glycoprotein in the immunoglobulin superfamily expressed on B cells throughout development and widely used as a marker of B cell lineage. CD19 functions as a key signaling component of the B cell receptor complex and helps regulate B cell activation and differentiation. CD19 is highly expressed in many B cell malignancies—including lymphomas and leukemias. CD19 is an important target for immunology research and therapeutic development. Conigen provides recombinant CD19 proteins to support CAR-T detection, antibody binding studies, assay development, and antibody discovery.

Human CD19 His dimer ELISA

Example QC data shown. See individual product pages and datasheets for target-specific QC results.

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Available formats

Soluble CD19 ectodomain dimer CSPâ„¢ (Conigen Soluble Protein)

  • Human
  • Mouse
  • Cynomolgus macaque
  • Rhesus macaque

Tag options

  • His
  • His-Avi
  • Biotinylated (His-Avi)

Available CD19 Products

ProductTagSpeciesProduct CodeDetailshf:tax:product_taghf:tax:pa_species
Biotinylated CD19His-AviBCSP-24125-03Show detailshis-avi
CD19HisMouseCSP-124-01Show detailshismouse
CD19HisHumanCSP-24125-01Show detailshishuman
CD19His-AviHumanCSP-24125-03Show detailshis-avihuman
CD19HisCynomolgus/Rhesus MacaqueCSP-25291-01Show detailshiscynomolgus-rhesus-macaque

Applications

  • Antibody discovery and characterization (CAR-T detection, screening, specificity testing, and binding evaluation for CD19-targeting antibodies)
  • Binding and affinity studies (ELISA, SPR, and BLI workflows for CD19-specific antibody binding, ranking, and competition studies)
  • Assay and reagent development (CAR-T detection by flow cytometry, ELISA development, assay optimization, and QC workflows for CD19-binding reagents)
  • Animal immunization (RUO) (as an immunogen to support generation of CD19-targeting antibodies)

Quality Control and Specifications

Quality Control Testing

  • Purity assessment (greater than 90% dimer formed as determined by SDS-PAGE under reducing and non-reducing conditions)
  • Bioactivity testing (binding activity confirmed by flow cytometry for CAR-T detection, ELISA and SPR  for CD19–specific antibodies, including reported EC50 and KD values)
  • Lot-specific documentation provided in downloadable product datasheets

Product Specifications

  • Format: extracellular domain cis-dimers of CD19
  • Expression host: HEK293T (mammalian)
  • Construct: soluble extracellular domain (ECD) dimer fused with a proprietary dimer motif to mimic the native conformation
  • Formulation: 0.22 μm filtered PBS, pH 7.4
  • Storage & shipping: shipped frozen on dry ice; store at −80°C

About Conigen Soluble Proteins

Engineered dimeric proteins with quaternary structures

  • Increase functional activity
  • Improve binding avidity for better detection sensitivity
  • Compact size dimer motif
  • Fc-free to avoid FcR binding
  • Glycan-free dimer motifs to avoid target epitope masking

 

Learn more about the CSPâ„¢ (Conigen Soluble Protein) Platform

Choosing the right CD19 format

Biotinylated vs Standard

Choose a biotinylated format if you:

  • perform flow cytometry
  • need immobilization for SPR, or BLI
  • want controlled orientation of the soluble protein
  • require consistent epitope presentation

 

Choose a standard (non-biotinylated) format if you:

  • perform both solid-phase and solution-phase binding or screening assays
  • perform SPR, BLI
  • want the simplest protein format

FAQs

Conigen’s dimerized proteins are engineered to replicate the native, cell-surface conformation of proteins more closely than monomeric ectodomains.

In practice, dimerized CD19 typically delivers:

  • Higher binding potency
  • Improved assay sensitivity
  • Wider assay windows

Conigen offers CD19 proteins in multiple tag formats, including His-tagged and His-Avi-tagged and biotinylated catalog dimers.

Additional tags such as Fc, Flag, HA, or Myc can be provided through custom expression to match your assay or conjugation needs.

Our recombinant proteins are produced using gene sequences originating from a variety of species including human, mouse and non-human primates. All proteins are expressed in mammalian cells to ensure consistent and relevant post-translational modifications.

Each CD19 protein dimer is bioactivity-verified through antibody binding ELISA, with QC-reported EC50 ranges demonstrating potent, specific recognition by anti-CD19 monoclonal antibodies. SPR/BLI workflows are supported as downstream affinity applications.

Our CD19 recombinant proteins have been used by customers in research applications, including flow cytometry-based assays to study CAR-T cells. However, assay performance and suitability depend on the specific experimental design and conditions. We recommend that customers validate the protein for their intended use.

Yes. CD19 proteins can be customized through Conigen’s CSP™ platform.

Lead time varies by format and scale. Catalog CD19 can be ordered directly and will ship within 2-3 business days of sales order receipt.

Custom CD19 and larger orders will follow a defined project workflow, but will generally be shipped 4-6 weeks following request. Contact us for a precise delivery estimate.

You can order CD19 proteins directly through the product page using Add to Cart or Add to Quote. For purchasing support or custom CD19 formats (alternate tags, variants, or assay-specific constructs), email [email protected] or submit a request through our Custom Project form.

Recombinant CD19 proteins have been used by customers in research settings as immunogens for antibody development. However, immunogenicity and antibody responses depend on multiple factors, including protein format, host species, and immunization protocol. Customers should perform their own validation to determine suitability for their intended application. 

Need help selecting the right CD19 protein for your assay?

Contact Our Team