Quantitation of low abundant cytokines in human blood samples using SMC ®high sensitivity immunoassays

Abstract

Abstract Quantitation of biomarkers in blood is crucial for the understanding of inflammatory diseases, which can lead to exploration into new therapeutic applications. Although the mechanism of disease pathogenesis may be unknown, pro-inflammatory cytokines (IL-1, IL-6, IL-17, IL-18, IL-23, IFN-γ, and TNFα) and anti-inflammatory cytokines (IL-4, IL-10, and IL-13) have been implicated in the pathogenesis of a variety of diseases. In basic research, standard immunoassays, such as an enzyme-linked immunosorbent assay (ELISA), have provided valuable understanding of both normal and pathological processes for many decades. However, in more recent decades, new immunoassay technologies have uncovered numerous biomarkers, such as cytokines, in blood that were once undetectable using traditional ELISAs. In this study, we have developed high-sensitivity immunoassays, using Single Molecule Counting (SMC ®) technology, to meet this new challenge of quantifying low abundant proteins in blood. The SMC ®IL-4, IL-17A and IL-23 assays consistently demonstrate LLoQ of 0.04 pg/mL, 0.03 pg/mL, and 0.1 pg/mL, respectively. More importantly, these assays were able to accurately quantify cytokines in healthy and patient samples, which were once not quantifiable using traditional ELISAs. Most notably, the dynamic range of these ultrasensitive SMC ®kits allowed quantitation of both healthy and disease blood samples in a single assay. In summary, SMC ®high sensitivity cytokine immunoassay kits can provide a powerful non-invasive biomarker tool in studying inflammatory diseases.