🧪 Antibody techniques

The high specificity of the antigen-antibody bond makes use of antibodies as a lab technique high on the list. Antibodies are used with proteins as a labelling method to detect presence of the target moiety (in biochemical reactions, testing or disease detection), or with whole tissue samples to detect presence of specific organelles for visualisation under a microscope.

 

Immunoassays

Assays are carried out in multi-well plates to detect the presence of a specific antigen, against which an antibody is added. If the antibody binds to the antigen, it causes a shift in a reporter enzyme added or linked to it, resulting in a colour change quantifiable by a spectrophotometer.

Antigens are any identifiable, specific parts of a molecule, and can be found on proteins, tissue samples, patient samples, pathogens, etc. Antibodies recognise antigens specific to them. The antigen-antibody relationship is at the heart of an organism’s self-identification and identification of invading species.

 

The enzyme-linked immunosorbent assay (ELISA) is a common immunoassay used to detect antigens in samples. It relies on adding the samples to a multi-well plate made of polystyrene, that can immobilise the antigen-containing molecules. The specific antibody is then added and allowed to bind, if it is to bind. After washing away the unbound molecules, the reporter enzyme is added to…