Anti-IA2, RIA

The DIAsource anti-IA2 kit is a direct assay based on the principle of radioligand assays. Highly purified human recombinant IA2 (intracellular fragment of IA2) is labeled with 125-Iodine.

This tracer is used in excess and bound by the IA2 autoantibodies of the sample. The DIAsource anti-IA2 tracer meets the highest requirements with regard to purity, enzymologic identity, fast reaction kinetics, cross reactivity at zero level and stability.

These are the main prerequisites for the specific binding of the tracer and its exclusive recognition by the IA2 autoantibodies of the sample.

By adding dissolved Protein A which binds to the Fc moiety of the autoantibodies, sandwich-type complexes are formed. 

By adding a precipitation buffer the immune complex will be precipitated as a solid phase which facilitates the simple separation of the bound fraction (B) by centrifugation.

After removing the supernatant which contains the non-bound tracer by aspiration or decantation, the radioactivity of the remaining precipitate is measured.

The concentration of IA2 autoantibodies (anti-IA2) in the sample is reflected by the specifically bound tracer amount. The radioactive signal (cpm) of the bound fraction (B) is proportional to the autoantibody concentration. No immune complex is formed if autoantibodies against IA2 are absent in the sample, as the tracer binds solely to IA2 autoantibodies, but not to Protein A.

A standard curve with a range of 0.01 - 60 U/ml is established by measuring cpm respectively the binding B/T % of the calibrators 1 - 5. The anti-IA2 concentration value of the patient’s sample is directly read off against this curve.