Single Molecule Arrays for ultra-sensitive detection of rat cytokines in serum.

Rats are used as animal models for many human diseases. Cytokines can serve as biomarkers indicative of these diseases or disease states. Techniques for measuring cytokine expression levels often do not provide the sensitivity needed to measure these biomarkers in biological fluids because the concentrations of many cytokines are below the detection limits of conventional methods. In this paper, we present ultra-sensitive digital immunoassays using Single Molecule Arrays (Simoa) for seven rat cytokines: TNF-α, IL-10, IL-17F, GM-CSF, IFN-γ, IL-4, and IL-1α. These ultra-sensitive immunoassays have limits of detection (LODs) in the femtomolar range and provide the ability to measure rat cytokines in serum below the LODs of conventional immunoassays. We also measured these cytokines in healthy rat serum to obtain baseline levels. The ability to measure cytokines present at low concentrations in rat serum will facilitate future studies of disease using rats as animal models.