INTENDED USE

Human IgG3 ELISA Kit from Innovative Research is intended for the quantitative determination of total human IgG3 (immunoglobulin G subclass 3) antigen in serum, plasma, hybridoma cell supernatants, ascites or other biological fluids. The assay does not detect immunoglobulins of other classes or subclasses.  For research use only.

BACKGROUND

IgG3 is one of the four subclasses of immunoglobulin G (IgG), which is a major class of antibodies involved in immune responses [1].   IgG3 is the most potent subclass in terms of activating the classical complement pathway. The long hinge region allows IgG3 to more easily activate C1q, the first protein in the complement cascade, which leads to the activation of the complement system [2].   IgG3 is typically produced during the initial immune response to an infection or vaccine Studies have shown that binding of IgG3 has the most important role in binding to SARS-CoV-2 antigens and this correlates strongly with viral neutralization in vitro indicating that high IgG3 concentrations may be highly efficacious therapy [3].   

ASSAY PRINCIPLE

Human IgG3 in samples will bind to the biotinylated capture antibody which is bound to the avidin on the plate. After appropriate washing steps, horseradish peroxidase labeled polyclonal anti-human IgG antibody binds to the captured protein. Excess antibody is washed away and TMB substrate is used for color development at 450nm. A standard calibration curve is prepared along with the samples to be measured using dilutions of human IgG3. Color development is proportional to the concentration of IgG3 in the samples. The assay measures total human IgG3 antigen in the 0.5‑500 ng/ml range. If the unknown is thought to have IgG3 levels greater than 500ng/ml, dilutions may be made in blocking buffer before use. A 1:800,000-1:200,000 dilution for normal human plasma is suggested for best results.

Sensitivity: The minimum detectable dose (MDD) was determined by adding two standard deviations to the mean optical density value of twenty zero standard replicates (range OD₄₅₀: 0.052-0.056) and calculating the corresponding concentration. The MDD was 0.093 ng/mL.

Specificity: This assay recognizes human IgG3.  This assay demonstrates 3% cross reactivity with total human IgG and purified IgG4.  Pooled normal plasma from horse, bovine, porcine, sheep, rabbit, Syrian Hamster, mouse, rat and Cynomolgus monkey, no significant cross-reactivity was observed.

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This material is sold for in-vitro use only for manufacturing and research. This material is not suitable for human or animal use. While we make every effort to ensure the safety of our products, we recommend handling any biological materials with standard precautions as if capable of spreading infectious disease. The statements herin are offered for informational purposes only to be used solely for your consideration, investigation, and verification.

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