Antibody-antigen Interactions detection

Immunoassays employ monoclonal or polyclonal antibody preparations (Chapter 13) to detect and quantify the product (Box 7.1). The specificity of antibody-antigen interaction ensures good assay precision. The use of conjugated radiolabels (RIA) or enzymes (EIA) to allow detection of antigen-antibody binding renders such assays very sensitive. Furthermore, when compared with... 

Immunoassays make use of the high specificity of antibody-antigen interactions. Also, coupled reactions are often used to introduce an element of amplification in the detection signal, giving the assays highly desirable properties of specificity and sensitivity. The antibody-antigen interactions can be carried out either in solution or in the solid phase in the latter, the immobilised species can be either the antigen or antibody. 

Grosjean L, Cherif B, Mercey E, Roget A, Levy Y, Marche PN, Villiers MB, Livache T. A polypyrrole protein microarray for antibody-antigen interaction studies using a label - free detection process. Anal. Biochem. 2005 347 193-200. 

Antibody-based electrochemical detection has been used in many applications for many years. In this section, we present a representative selection of useful applications using different types of antibody-based electrodes and detection principles. In particular, the type of antibody-antigen interaction, the surface modification, and the sensor performance will be addressed. 

On the basis of an enzyme thermistor, Mattiasson et al. (1977) developed one of the first immunosensors. Immobilized antibodies against albumin are placed in a column and set into an ET. After injection of an albumin-sample and a known amount of enzyme-labeled albumin, both are separated from the sample matrix by antibody-antigen-interaction. After injection of a substrate, the change in heat is a measure of analyte concentration. The less heat produced means that more albumin has been bound. An elution step regenerates the ELISA. Due to its thermal detection principle, the procedure is called TELISA (thermometric enzyme-linked immunosorbent assay). Figure 3 shows the principle of the TELISA procedure in its sandwich configuration. 

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