ELISA vs. ELISpot

ELISAs use antibodies to detect the presence and concentration of a protein in a liquid sample. In the most common form, antigens are applied to a stable surface (usually a microtiter plate). Then the corresponding antibody, linked with an enzyme, is added to form a complex. Finally, the enzyme’s substrate is added, which produces a measurable reaction, usually in the form of a color change.

ELISpots also utilize antibody-enzyme reactions. However, instead of measuring the concentration of protein in a sample, they measure the number of cells secreting the cytokine of interest in a sample. Antigens are applied to the plate surface, and when samples are added, cells settle on the bottom of the wells. The cytokines secreted by the cells are captured by the surrounding antigens. After the appropriate incubation time, the cells are removed and the secreted cytokine is detected using a detection antibody linked with an enzyme. The enzyme’s substrate is added, producing a reaction. The end result is visible spots on the on the surface of the plate. Each spot corresponds to an individual cell that was secreting the target protein.

The information provided by ELISpot kits is applicable to various fields of study including: transplantation, vaccine development, T-cell regulation analysis, autoimmune disease, cancer, allergy, and viral infections. These kits are highly sensitive and easy to use.