Immunoglobulin J Chain ELISA Kit (IGJ)

Full Name: Immunoglobulin J Chain ELISA Kit (IGJ)
Reactivity: Human
Sample Type: Plasma, Tissue Homogenates, Serum, Biological Fluids
Sensitivity: 0.938 ng/ml

INTRODUCTION

The immunoglobulin J chain (IGJ) is required for the polymerization of IgM and IgA, two antibody classes that function to neutralize pathogens in extracellular fluids. It is expressed by plasma cells and associates with monomeric IgM and IgA through disulfide bonds, enabling their pentamerization. The pentameric structure of IgM and IgA mediated by J chain confers enhanced complement-activating and pathogen-binding capabilities compared to monomeric forms. Specifically, pentameric IgM has 10 antigen-binding sites compared to 2 for IgG, allowing high avidity interactions with antigens.

Similarly, pentameric IgA can bind pathogens coated with IgA from multiple angles, facilitating immune exclusion. IGJ also contains a binding site for the poly-Ig receptor (pIgR), an epithelial transport protein that carries pentameric IgM and IgA across mucosal barriers into secretions. Thus, by promoting Ig polymerization and pIgR binding, IGJ enables transport of highly effective polymeric Ig isotypes to mucosal sites.

Given its indispensable role in IgM and IgA synthesis and secretion, deficiencies in IGJ impair mucosal immunity. Selective IgA deficiency, the most common human primary immunodeficiency, can arise from mutations in IGJ preventing IgA polymerization. Additionally, IgJ knockout mouse models exhibit defective mucosal immune responses, including reduced levels of secretory IgA and IgM in luminal secretions, diminished immune exclusion, and increased susceptibility to mucosal infections. The protective functions of IgJ extend beyond mucosal sites, as serum IgM levels are also reduced in knockout models. Therefore, IGJ is essential for optimal IgM and IgA-mediated humoral immune defenses against pathogens at mucosal surfaces and systemically.

INTENDED USE

Human Immunoglobulin J Chain ELISA kit can measure concentrations of IGJ (Immunoglobulin J, IGCJ) present is plasma, serum, biological fluids or tissue homogenate samples.

CONTENT

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- IGJ.
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.

TYPICAL RESULTS

For this Immunoglobulin J Chain ELISA kit, it is recommended that a standard curve is generated for each assay carried out.

Standard Curve: 0, 1.562, 3.125, 6.25, 12.5, 25, 50, 100 ng/ml.
Reactivity: Human
Sensitivity: 0.938 ng/ml
Range: 1.563 – 100 ng/ml
Principle: Sandwich, Double Antibody
Application: Research Use Only.

ASSAY CHARACTERISTICS

– Specificity: Highly specific for IGJ, no cross reactivity or interference between IGJ and analogues was detected.
– Recovery: Serum (95 – 103%), EDTA Plasma (85 – 104%), Heparin Plasma (87 – 102%).
– Linearity: Serum (88 – 102%), EDTA Plasma (82 – 94%), Heparin Plasma (80 – 95%).
– Precison Intra-Assay: CV < 8%
– Precison Inter-Assay: CV < 10%

REFERENCES

Secondary structure of the immunoglobulin J chain. Proc Natl Acad Sci U S A. 1985 Sep;82(17):5905-9. Zikan J., et al.
Presence of J chain in human lymphoid cells. Clin Exp Immunol. (1980) 39 (2): 371-85. Mestecky J., et al.
Quantitative immunohistochemistry of immunoglobulin- and J-chain-producing cells in human parotid and submandibular salivary glands. Immunology. (1980) 39 (2): 129-40. Korsrud F.R. and Brandtzaeg P.
IGJ suppresses breast cancer growth and metastasis by inhibiting EMT via the NF‑κB signaling pathway. Int J Oncol. (2023) 63 (3): 105. Wang M., et al.

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