CD19 ELISA Kit (Cluster Of Differentiation 19)

Full Name: CD19 ELISA Kit (Cluster Of Differentiation 19)
Reactivity: Human
Sample Type: Serum, Tissue Homogenates, Biological Fluids, Plasma
Sensitivity: 0.094 ng/ml


Cluster of Differentiation 19 (CD19) also described as B-lymphocyte antigen CD19 is a transmembrane protein. It is expressed B lineage cells where it has two major roles. Firstly it decreases the threshold for B-cell receptor signalling pathways by working alongside CD19/CD21 complex and secondly, it recruits cytoplasmic signalling proteins to the membrane by acting as an adaptor protein. It is regarded as a biomarker for lymphoma diagnosis and B-lymphocyte development. It is also used as target for immunotherapies for leukemia treatments.

The N-terminal extracellular region contains the immunoglobulin light chain constant region that pairs with V H segments on developing antibodies during B-cell development. The C1-domain portion consists of six conserved cysteine residues forming a disulfide bridge, which anchors this segment of the molecule to an intracellular protein called cytokeratin 19 (CK19). Researchers have discovered that following treatment with chemotherapy, the levels of CD19 in the bloodstream increase.

CD19 is located on chromosome 16 (short arm). It contains fifteen exons, nine of which encode the cytoplasmic domains and four encode the extracellular domains. It is 95kd Type I transmembrane with two extracellular domains and a 240 amino acids cytoplasmic tail. It is expressed during the complete duration of B cell development. The expression in mature B cells is found to greater than threefold higher than that of immature B cells.

The main function of CD19 is to translocate between the endoplasmic reticulum and the cell surface where it acts as a receptor for antigen. Other functions include: CD19 protein binds IgG, IgA and complement factor C4 as well as various cytokines such as IL-1α and TNF. The protein is involved in activation of B cells by antigen-stimulated B cells. It also functions in binding to microbial cell wall components such as lipoteichoic acid (LTA) which promotes the development of macrophages into dendritic cells.


Human CD19 ELISA kit can measure concentrations of cluster of differentiation 19 (CD19, B-lymphocyte antigen, CVID3, B4, T-cell surface antigen Leu-12) present is human plasma, serum, biological fluids and tissue homogenates.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • One 96-Well Plate: Pre-coated with anti-CD19 antibody.
  • Standards: Lyophilized recombinant.
  • Sample/Standard Dilution Buffer.
  • Biotinylated-labelled Antibody.
  • Antibody Dilution Buffer.
  • HRP-Streptavidin Conjugate (SABC).
  • SABC Dilution Buffer.
  • TMB Substrate.
  • Wash Buffer (25x).
  • Plate Sealer.
  • Product Instructions.


For this CD19 ELISA kit it is recommended that a standard curve is generated for each assay carried out.

Standard Curve: 0, 0.156, 0.312, 0.625, 1.25, 2.5, 5, 10 ng/ml.

Reactivity: Human
Sensitivity: 0.094 ng/ml
Range: 0.156 – 10 ng/ml
Principle: Sandwich
Application: Research Use Only.


– Specificity: Highly specific for CD19, no cross reactivity or interference between CD19 and analogues was detected.
– Recovery: Serum (85 – 103%), EDTA Plasma (85 – 100%), Heparin Plasma (85 – 101%).
– Linearity: Serum (85 – 105%), EDTA Plasma (81 – 100%), Heparin Plasma (86 – 103%).
– Precison Intra-Assay: CV < 8%.
– Precison Inter-Assay: CV < 10%.
– Stability: Less than 10%.


  1. CD19 antigen in leukemia and lymphoma diagnosis and immunotherapy. Leuk Lymphoma. (1995) 18 (5-6): 385-97. Scheuermann R.H. and Racila E.
  2. CD19/BAFF-R dual-targeted CAR T cells for the treatment of mixed antigen-negative variants of acute lymphoblastic leukemia. (2022) 36 (4): 1015-1024. Wang X., et al.
  3. CD19-targeted CAR regulatory T cells suppress B cell pathology without GvHD. .JCI Insight. (2020) 5 (14): e136185. Imura Y., et al.
  4. Optimized CD19/CD22/CD3 antibody. (2022) 140 (16): 1750-1751. Müller D.


Online Enquiry Form

"*" indicates required fields

Please check mark information required:


Your secretory IgA ELISA gave good results and I was also really impressed with how quickly we received it.

L. Johnston
PhD Student / University of Glasgow

It is refreshing to know that you have a technical team that is very knowledgeable. I have already recommended your company to other researchers in our department.

Dr. P. Anderson
Lecturer / University College London (UCL)

I am a first time user and found that your instruction manual was very easy to follow. The insulin ELISA assay performed well and I was happy with the results that were generated.

J. Thomas
Senior Technician / Addenbrooke’s Hospital

I carried out a pilot study comparing the performance of many ELISA assay's from different suppliers and found your kits to be one of the better performers. We observed good linearity and tight replicates.

Dr. C. Davies
Lead Scientists / AstraZeneca

You are my first point of contact when I am looking to purchase ELISA. You have such an easy and simple system, yet it is very effective.

A. Shaw
Purchasing / University of Oxford