Age-dependent Cytokine Expression in Response to Foot-and-mouth Disease Virus in Bovine Peripheral Blood Mononuclear Cells

The severity of foot-and-mouth disease virus (FMDV) infections differs between calves and cattle. Here, we compared immunological responses to FMDV in bovine peripheral blood mononuclear cells (PBMCs) from juvenile cattle (7–9 months) and calves (3–4 months). PBMCs were collected from cattle and inoculated with serotype O FMDV and incubated for 0, 1, 3, 6, 12, 24, 48, 72, and 96 h. At each time point, total RNA was isolated from PBMCs and the mRNA expression of six cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, and IL-10) was evaluated. Th1 (IFN-γ and IL-2) and Th2-related (IL-4 and IL-10) cytokine levels were more prominent in juvenile cattle than in calves. In particular, IL-2 and IL-10 from juvenile cattle were significantly (P<0.001) higher than those from calves at 48 and 24 hpi, respectively. Therefore, the juvenile cattle showed remarkable Th1 and Th2-related immune response than calves within 48 h after FMDV infection.