Functional IGFBP-3 LIA Assay


The IGFBP-3 LIA Assay Kit determines the real functional and effective bioactive IGFBP-3, functional in terms of binding ability of the mainly interesting natural ligand, namely IGF-I. The Eagle Biosciences functional IGFBP-3 LIA Assay kit sample types are human Serum, Heparin or EDTA plasma. The Eagle Biosciences Human functional IGFBP-3 LIA Assay kit is for Research Use Only.

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Functional IGFBP-3 LIA Assay

The Functional IGFBP-3 LIA Assay is For Research Use Only

Size: 1×96 wells
Sensitivity: 0.18 µg/L
Incubation Time: 3.5 hours
Sample Type: Serum, EDTA or Heparin Plasma
Sample Size: 10 µL

Manufactured by Mediagnost

Assay Principle

The Eagle Biosciences IGFBP-3 LIA Assay Kit utilizes specific and high affinity antibodies for IGFBP-3, the antibodies are immobilized on the microtitre plate. The ligand, biotinylated IGF-I is pre-dispensed in excess into the needed wells. The sample is diluted outside within a special dilution buffer (Sample Buffer PP); all naturally bound IGFs are thereby released from their binding proteins. By adding an aliquot of such diluted sample with free IGFBP-3 to the ligand containing wells, the biotinylated IGF-I occupies all existing specific binding sites of the IGFBP-3. All IGFBP-3 molecules are bound afterwards to the microtitre plate, however by using a Strepavidin-Peroxydase-(POD)-Conjugate only the complexes of IGFBP-3/biotinylated IGF-I are involved in signal generation (in the closing POD-substrate reaction), thus, only functional IGFBP-3 is being quantified.

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Additional Information

Assay Background

All currently existing IGFBP-3 immunoassays use the binding of specific anti-IGFBP-3 antibodies for signal generation and thus IGFBP-3 quantification. The failure of differentiation between complete IGFBP-3 molecules and their respective fragments (derived physiologically due to the different proteases activities) is unavoidable in this system. Because one molecule IGFBP-3 can be cleaved in several fragments often false high quantitative values are measured. Based on this methodology it is not possible to differentiate between high IGFBP-3 levels in fact, or, a high degree of fragmentation. The incidental attempts to use monoclonal antibodies with a binding region represented only by the intact IGFBP-3 molecule are indirect, imprecise and insufficient. The activities of all effective proteases, which have different sites of action and therefore generate different kind of fragments, are disregarded.

The Eagle Biosciences IGFBP-3 LIA Assay Kit however enables to determine the real functional and effective bioactive IGFBP-3, functional in terms of binding ability of the mainly interesting natural ligand, namely IGF-I.

The new test principle (patent pending DE19719001) uses anti-IGFBP-3 antibodies immobilized on the microtitre plate and biotinylated IGF-I as ligand. The IGFBP-3 of the sample is bound to the microtitre plate, and only concomitant bound, by IGFBP-3, biotinylated IGF-I gives the specific signal of the test. Therefore only functional IGFBP-3 is quantificated. The patented test format ensures an easy and reliable performance, simply like a conventional ELISA kit. Advanced and time- as well as labor-intensive biochemical analysis (e.g., by size chromatography or Western Blots, etc.), which moreover only allows an estimation of concentrations, has become redundant.

Exemplary Values:
Exemplary values of fragmented IGFBP-3 in relation to total IGFBP-3 of healthy blood donors are shown in figure 1. It is demonstrated that about 25% of the IGFBP-3 is fragmented and thus could be detected by biotinylated IGF-I.

Package Inserts

Please note: All documents above are for reference use only and should not be used in place of the documents included with this physical product. If digital copies are needed, please contact us.

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