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KACTUS: CD19 Proteins

KACTUS: CD19 Proteins

High-Quality Recombinant CD19 Proteins for B-Cell Malignancy Research and Antibody-Based Therapy Development

CD19 is a pivotal transmembrane glycoprotein involved in B cell activation and humoral immune responses, making it a critical focus for therapies targeting B-cell malignancies such as chronic lymphocytic leukaemia (CLL), acute lymphoblastic leukaemia (ALL), and various non-Hodgkin lymphomas. Its universal expression throughout B-cell development and pivotal role in activating signalling pathways make it an ideal focus for developing antibody-based treatments, including bispecific antibodies, ADCs, Fc-engineered antibodies, and CAR-T cell therapy.

KACTUS’ high-quality CD19 proteins are designed for applications such as antibody screening, CAR-T cell therapy development and affinity measurements. Validated through ELISA, SPR and flow cytometry, these CD19 proteins ensure reliability and efficacy in your research.

Product Features

KACTUS’ recombinant CD19 protein products offer versatility and reliability, available in various species, including human, cynomolgus, rhesus macaque and mouse. These CD19 proteins have been validated for high binding affinity by SPR and ELISA. Their FITC-compatible human CD19 can be used for CAR detection via FACS. With off-the-shelf catalog products in stock, they ensure short lead times to meet your research needs efficiently.

  • Various Species – Human, Cynomolgus, Rhesus Macaque, Mouse
  • High Monomer Rate – Expressed with small tag (His) with optimal monomer rate
  • High Binding Affinity – High binding affinity verified by SPR and ELISA
  • CAR Detection – FACS Compatible Human CD19 for CAR Detection
  • In Stock – Off-the-shelf catalog products with short lead time
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Product Validation Data

KACTUS’ team has performed extensive binding affinity and activity verification of their CD19 protein products including FACS detection of anti-CD19 CAR cells as well as ELISA and SPR verification using anti-CD19 antibodies. Their CD19 products also undergo purity and identity testing using HPLC and Bis-Tris page.

Detection of Anti-CD19 CAR cells using FITC-compatible human CD19

Figure 1. FITC-Compatible Human CD19 (100 µL, 10 µg/mL) was used to detect the positive rate of 1×10⁶ anti-CD19 CAR cells. FITC-labeled irrelevant protein (100 µL, 10 µg/mL) and non-transfected 293T cells were used as negative controls. Results show a positive detection rate of 96.79%.

High binding affinity verified by ELISA and SPR

Figure 2. Dose-response curve for Coltuximab, hFc Tag, using immobilised Human CD19, His Tag at a concentration of 2 µg/mL (100 µL/well) on the plate. Results show an EC50 of 5.3 ng/mL, demonstrating the protein’s high binding affinity and suitability for antibody screening applications.
Figure 3. Dose-response curve for FMC63, mFc Tag, using immobilised Human CD19, His Tag at a concentration of 2 µg/mL (100 µL/well) on the plate. Results show an EC50 of 10.0 ng/mL, highlighting the protein’s high binding affinity and its suitability for applications such as antibody screening and therapeutic development.

Figure 4. Dose-response curve for Inebilizumab, hFc Tag, using immobilised Human CD19, His Tag at a concentration of 1 µg/mL (100 µL/well) on the plate. Results show an EC50 an 11.5 ng/mL, demonstrating the protein’s high binding affinity and its effectiveness in antibody screening assays.
Figure 5. SPR assay showing binding interaction between an anti-CD19 antibody, hFc Tag, captured on a CM5 Chip via Protein A, and Cynomolgus/Rhesus macaque CD19, His Tag. The binding affinity was determined using a Biacore T200 and revealed an affinity constant of 0.46 µM, demonstrating the robust interaction between the antibody and CD19 protein.

Caltag Medsystems is the distributor of KACTUS products in the UK and Ireland. If you have any questions about these products, please contact us.

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