ACT 2024 -- Elevated concentrations of cytokines indicate activation of pathways associated with inflammation, and the measurement of cytokines has been widely used to understand and to monitor the effects of therapeutic treatments. Validated methods for the evaluation of biomarkers such as cytokines require a biological matrix relevant to the physiology and distribution of the biomarker. The source of the biomarker can potentially influence the validation process and subsequently the robustness of the method. Endogenous nonhuman primate (NHP) cytokine samples and ex vivo stimulated NHP samples [whole blood and peripheral blood mononuclear cells (PBMCs)] were generated and compared to recombinant cytokines. These samples were assessed across kits and assay format for cytokine expression to evaluate the utility of these matrices in validating methods. The NHP endogenous matrix, stimulated matrix and spiked matrix using recombinant material all generated methods that reliably detected cytokines in study samples and demonstrated similar patterns of cytokine expression. While endogenous samples are preferred, it can be difficult to obtain an identical matrix to that of the study samples. The comparison data demonstrate that the cytokine expression in ex vivo generated matrices are acceptable and scientifically appropriate for method validation.

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