Dendritic cells fight foot and mouth disease
Foot and mouth disease virus is a devastating disease of livestock for several reasons. It is highly infectious and the acute phase is followed by a time where there are no symptoms. Carrier animals can therefore pose a significant risk to healthy stock. Moreover, the virus can persist in straw and hay for up to 20 weeks. The EC project FMD TROPISM set about trying to unravel the complex molecular biology surrounding viral movement and persistence in the host. This, they hoped would lead to the prevention or cure of this dangerous carrier state. Scientists at the Institute of Virology in Switzerland investigated the role of dendritic cells (DCs) in the shaping of the immune response. First, they investigated the way that FMDV interacts with DCs. These cells are important players in the mammalian immune response and they control lymphocytes that respond to specific antigens. Two variants of virus were studied. Results indicated that there was a more efficient uptake and binding of the virus if it was the HS-binding variant. It was also confirmed that uptake and retention of the virus is essential for induction of lymphocyte activity. Secondly, they focused on the interaction of FMDV with natural interferon-producing cells (NIPCs), also a type of dendritic cell. They discovered that interferon production was only induced when live FMDV was complexed with immune IgG, the most common type of antibody found in the system. Encouragingly, the presence of NIPCs and therefore interferon could constitute a form of innate or natural immunity. This could confer defence against the virus before the acquired immunity of antibody production was fully developed. These findings then constitute important factors in the possible development of new vaccination strategies. Efficient activation of specific immune defences may well provide the key to the eradication or effective control of this disease.
