Abstract
Three antigenic variants of foot-and-mouth disease virus, type A, strain 119, were demonstrated in Ouchterlony analyses utilizing serum collected from guinea pigs 7 days postinfection (DPI). Such antisera contain antibodies of the 19S class. Guinea pig antisera that contained antibodies of the 7S class were unable to distinguish between the antigenic variants. Similarly, 19S antibody was able to demonstrate antigenic differences in trypsin- and chymotrypsin-treated viruses that were not detected by 7S antibody-containing antisera.