Foot-and-mouth disease and beyond: vaccine design, past, present and future.

Abstract

The first experimental vaccines against foot-and-mouth disease were made in 1925 by Vallee, Carre and Rinjard using formaldehyde inactivation of tongue tissue from cattle infected with the virus. This method was essentially unaltered until the late 1940s when the important experiments by Frenkel in Holland showed that the quantities of virus required for vaccine production could be obtained from fragments of tongue epithelium incubated in vitro following infection with the virus. This major step made possible the comprehensive vaccination programmes which followed in Western Europe and which, in turn, resulted in the elimination of the disease from that part of the world by 1989. This spectacular success has led many to question whether other kinds of vaccine are required to control the disease worldwide. Such reservations ignore the danger to the environment associated with the growth of large amounts of virus. This can never be a zero-risk situation. Consequently, a vaccine which is not based on infectious virus as starting material has many attractions from safety considerations alone. In addition, a vaccine based on more fundamental considerations would not only be more aesthetically satisfying but could possibly provide an understanding at the molecular level of antigenic variation, still a problem in the control of the disease. The advances in our knowledge of the structure of the virus and the fragments which elicit a protective immune response now allow us to envisage a vaccine which does not require infectious virus and which protects against the multiple serotypes of the agent. Since antigenic variation is still a major problem in the control of the disease by vaccination, such a product would have important advantages over the current vaccines.