Towards the development of a new foot and mouth disease vaccine

The causative agent of foot-and-mouth disease is a picornavirus with a single-stranded positive sense RNA genome of about 8000 nucleotides. There are seven main serotypes of the virus and a large number of subtypes. Virus harvested from cultured cells, and chemically inactivated, forms the basis of modern vaccines. The present vaccines have successfully controlled virus outbreaks in endemically infected areas but are unstable and require refrigeration. Early studies have shown that the ability to stimulate neutralizing antibodies resides in only one of the four capsid proteins, VPl. Although a number of groups have attempted to produce subunit vaccines from VPl using genetic engineering techniques, VPl may not be sufficiently immunogenic for effective vaccination. More encouraging are the results that have been reported for synthetic peptides corresponding to defined regions of the VPl protein. Further development of these immunogens will be needed to produce a new vaccine that can compete in cost and effectiveness with the present FMD vaccines.