Insights into immune processes show how virus can be retained in the bodies of infected animals and cause persistent infection. Image Follicular dendritic cells, shown in yellow, in spleen tissue Detailed insights into how the Foot-and-Mouth Disease Virus (FMDV) interacts with immune cells aids understanding of how it can cause persistent infection in some animals. The findings, from a team at the Roslin Institute and Pirbright Institute, could inform the development of new vaccines that offer long-lasting protection against the highly contagious disease. Their outcomes could benefit farmers of African buffalo, whose herds can harbour the disease for five years or more following acute infection. Virus retention Researchers sought to understand how the virus that causes Foot-and-Mouth Disease (FMD) is retained and persists in tissues such as the spleen following infection. In studies in mice, they discovered that FMDV binds to cells, known as follicular dendritic cells, which are found in lymphoid tissues in the immune system. These cells behave almost like a spider’s web, trapping foreign particles and certain viruses for long periods of time so that other cells in the immune system can make immune responses against them. Analysis showed that the virus binds to a receptor molecule, known as CR2/CR1, on follicular dendritic cells. This was found to be essential for the cells to be able to trap and retain the virus, which in turn leads to a better, and longer-lived immune response. The scientists consider this helps the virus to persist in animals such as African buffalo and allows these animals to become carriers of the disease, which in turn poses a risk to other susceptible livestock. Our research has uncovered a key biological process by which the virus for Foot-and-Mouth Disease is able to remain in the immune systems of animals such as African buffalo. This could inform efforts to develop improved vaccines which, unlike current vaccines, provide longer term protection to safeguard livestock. Professor Neil MabbottRoslin Institute This research helps to bridge the knowledge gap of how the immune system deals with FMDV infection in large animals. Our extensive work in African buffalo, a natural host of the disease, allowed us to predict why and how persistence may occur and then test this theory in a small animal model. This has given us new insights into the immune responses to FMDV and could provide clues about how to increase vaccine protection longevity. Professor Bryan CharlestonPirbright Institute ** The Roslin Institute receives strategic investment funding from the Biotechnology and Biological Sciences Research Council and it is part of the University of Edinburgh’s Royal (Dick) School of Veterinary Studies. ** Related links Scientific publication Genetic finding could help beat fatal cattle infection Improved DNA reference aids African cattle research Image credit: Garibgazi/Wikimedia; Neil Mabbott
