What is the principle behind the enzyme-linked immunosorbent assay (ELISA)?

The principle behind the enzyme-linked immunosorbent assay (ELISA) is centered on antigen-antibody interactions. This technique is designed to detect and quantify specific proteins or antibodies in a sample. In an ELISA, the target antigen is attached to a solid surface. When the sample is added, any specific antibodies present will bind to the antigen, forming a complex.

Following this binding, a secondary enzyme-linked antibody that recognizes the primary antibody is introduced. This secondary antibody is conjugated with an enzyme that will react with a substrate to produce a measurable signal, usually a color change. This signal can then be quantified to determine the presence and concentration of the target protein in the sample.

This method is powerful and widely used in diagnostics due to its specificity and sensitivity. The success of ELISA hinges on the precise interactions between antigens and antibodies, making the understanding of these interactions crucial for interpreting results.