The ELISPOT assay (Enzyme-Linked ImmunoSpot) was originally developed as a means of detecting antibody-secreting B-cells. This technique was subsequently adapted to determine T-cell reactions to a specific antigen, usually in terms of the number of activated cells per million.
ELISPOT assays have several advantages over other methods of cytokine detection. They are highly sensitive and can provide single-cell resolution. They allow nearly in vivo assay conditions, and with modern ELISPOT analyzers, they also allow high sample throughput rates.
ELISPOT plates can be kept small and, by avoiding pre-coated plates and vials with concentrated buffers, they can be transport-friendly. In addition, an assay can be set up for several different cytokines in the same plate.
Most researchers use IFN-g production as an indication of single cell activation; however, ELISPOT techniques allow for a wide variety of secretions to be detected. Due to its flexibility, this technology can be used to gauge killer T-cell activity in viral studies or tumor-related research, to evaluate antibody production, or to determine Th1-Th2 balance.