Effect of Trypsin Treatment on the Antigenic Characteristics of Plaque Variants of Type O1 and Type Asia-1 Foot-and-Mouth Disease Viruses

Abstract

SUMMARYAntigenic differences were demonstrated between the large and small plaque variants of both types O1 and Asia-t foot-and-mouth disease viruses. Treatment of the large and small plaque variants of the viruses with trypsin essentially abolished the observed antigenic differences. Thus, these plaque variants have antigenically different trypsin.-sensitive determinants that may influence their immunogenicity and infection capabilities.

Sequence variation in the gene for the immunogenic capsid protein VP1 of foot-and-mouth disease virus type A.

“…Although this rate is high when compared to DNA viruses [presumably due to lack of proofreading activity in the RNA replicase (8)(9)(10)], it is no higher than mutation rates in other RNA viruses (9). Several research groups have suggested that under the pressure of field outbreaks mutants are selected that are not effectively neutralized in the immunized or convalescent animal populations (9)(10)(11)(12)(13). This "immune selection" may be accelerated by the existence of unvaccinated or only partially protected livestock or unprotected wild animal hosts situated near livestock production regions (3,12).…”