Foot-and-mouth disease virus causes a decrease in spleen dendritic cells and the early release of IFN-α in the plasma...

Foot-and-mouth disease (FMD) is a highly contagious and acute viral disease of cloven-hoofed animals. From an economical point of view, it is the most important disease of livestock worldwide. It is known that the virus interacts with dendritic cells, both in the natural host and in mice, but the impact of this interaction on the adaptive immune response is controversial. Currently available vaccines are based on inactivated forms of the FMD virus. Little is known about the differences between infectious and inactivated virus, in terms of dendritic cell subsets involved in immune response activation. The present work, which was carried out in the murine model, shows that live virus infection induces a reduction in splenic dendritic cell subsets. In addition, lymphocyte proliferation is inhibited in the early stages of infection associated with IFN-α induction, but is restored to normal values 5 days post-infection when pro-inflammatory cytokines was produced. In contrast, the inactivated virus increases the percentage of plasmacytoid dendritic cells in the spleen and the production of IL-10, which triggers the activation of a T regulatory response.