Mutant viruses provide clues to infectivity
Foot and mouth disease virus (FMDV) causes one of the most contagious animal diseases with important losses. It causes a high mortality in young animals due to myocarditis. After the acute phase, there is often a persistent infection without symptoms. Carrier animals also arise in those vaccinated and then exposed to FMDV. Obviously, the development of these hidden carriers presents a limit to any vaccination scheme implemented to control the spread of the disease. Researchers, as part of the project FMD TROPISM, studied aspects of persistence in carriers together with mechanisms of host cell recognition by the virus. One of the teams focused on the receptor binding sites of the virus in conjunction with integrins on the host cell surface. Integrins are very significant cell surface receptors that define the cell shape, mobility, and cell cycle regulation and they are thought to be an important factor in infectivity. In order to do this, they created recombinant viruses with mutations either side of the receptor binding site. The scientists observed the behaviour of the recombinant viruses in vivo and in vitro. They discovered, as suspected, that the amino acids on the viral coat and their arrangement were crucial for infectivity. In some cases, the arrangement on the virus coat was found to have changed in order to accommodate the mutations on the virus shell. Furthermore, the level of modified infectivity was linked to the particular change in the site. To elucidate the nature of the virus-host cell interaction and its role in infectivity is a big step. Further research and development can aid the successful implementation of a vaccination programme to help the eradication of this disease.
