Description
The cytokine ELISPOT (Enzyme-Linked ImmunoSPOT) assay is designed to enumerate cytokine-secreting cells in single cell suspensions of lymphoid tissue, central nerve system (CNS) tissue, bone marrow or preparations of peripheral blood mononuclear cells (PBMCs). The assay has the advantage of detecting only activated/memory T-cells and has the ability to detect cytokine release in response to antigen by a single cell thereby permitting direct calculation of responder T-cell frequencies. The high sensitivity and easy performance, allowing the determination of peptide-reactive T-cells without prior in vitro expansion, makes the ELISPOT assay eminently well suited to monitor T-cell responses. The higher sensitivity of ELISPOT in comparison to that of ELISA or intracellular staining is due to the plate-bound antibodies directly capturing the cytokine released by the cell before it is diluted in the supernatant, trapped by high-affinity receptors or degraded by proteases. The sensitivity of the assay lends itself to measurement of very low frequencies of cytokinesecreting cells (1/300,000)