Evaluation of non-classical analytes in nonhuman primate cytokine release assays

SOT 2025 -- The various formats of cytokine release assays (CRAs) are in vitro assays utilizing nonhuman primate (NHP) immune cells representing a novel, inexpensive and rapid means of evaluating the safety profile of potential therapeutics prior to preclinical animal studies. Classically, CRA design across all formats focused almost exclusively on the evaluation of analytes such as IFNγ, IL-2, IL-6 and TNFα to assess the risk of eliciting cytokine release syndrome (CRS) in vivo. However, when considering an in vitro assay to evaluate potential immunomodulation of a therapeutic on NHP immune cells, the inclusion of a wider array of analytes can generate not only important safety data but provide key mechanistic insights as well. In the current study, we evaluated several prevalent positive control compounds used in CRAs in a commonly utilized CRA format – liquid phase stimulation of NHP peripheral blood mononuclear cells (PBMCs). These positive controls were chosen for their ability to stimulate production of cytokines and chemokines outside those traditionally included in CRAs.