Abstract
•FMDV antigen induces recall cytokine responses in bovine blood cells.•mRNA induction peaked at 6h for IL-2 and IFN-γ, and 24h for IL-4 in PBMCs.•Protein level peaked at 72h for IL-2 and IL-4, and 96h for IFN-γ in whole blood.
The interest in analysing antigen-specific cytokine responses has substantially increased in recent years, in part due to their use in assessing vaccine efficacy. In the present study, the kinetics of IL-2, IL-4 and IFN-γ expression was determined in bovine PBMCs by real-time PCR and in whole blood by cytokine-release assay after in vitro stimulation with recall foot-and-mouth disease virus (FMDV) antigen. The results showed that the cytokine mRNA of IL-2 and IFN-γ in PBMCs were induced early (peak induction at 6h), whereas the IL-4 mRNA showed delayed induction (peaked at 24h). In contrast, the kinetics of cytokine proteins in whole blood was different and required the accumulation of the proteins before being optimally detected. The peak accumulation of cytokine protein in whole blood was recorded at 72h for IL-2 and IL-4, and 96h for IFN-γ. The findings of this study are of importance when selecting an optimal time points for measuring antigen-specific cytokine expression in cattle.