MSD offers a range of individual assays utilizing U-PLEX Antibody Sets that provide a rapid and convenient method for measuring biomarkers in complex matrices. The individual assays are offered on MSD GOLD Small Spot Streptavidin Plates and use the same antibody sets and diluents as the U-PLEX multiplex assays. This allows for efficient transfer between the individual assay and a higher throughput multiplex configuration. Typical of assays developed on the MSD platform, the individual assays have high sensitivity, excellent precision, provide up to five-logs of linear dynamic range, and require minimal sample volume. Interleukin-18 (IL-18) is an 18 kDa cytokine and a co-stimulatory factor that is produced in Kupffer cells, activated macrophages, keratinocytes, and intestinal epithelial cells. One of the main functions of IL-18 is to promote the production of IFN-γ from T and NK cells, particularly in the presence of IL-12p70. IL-18 also promotes the secretion of other proinflammatory cytokines like TNF-α, IL-1β, and GM-CSF that enhance the migration and activation of neutrophils during microbial infections. In addition, IL-18 enhances cytotoxic activity and proliferation of CD8+ T and NK cells and has been shown to stimulate the production of IL-13 and other Th2 cytokines. Dysregulation of IL-18 may therefore contribute to inflammatory-associated disorders, unchecked infections, autoimmune diseases such as rheumatoid arthritis, acute and chronic kidney injury, cancer, and pathogenic conditions related to metabolic syndrome. The U-PLEX NHP IL-18 Assay provides the components for the quantitative determination of both natural and recombinant IL-18 in Cynomolgus monkey and Rhesus monkey serum, plasma, and cell culture supernatants.