Comparative Biochemical and Serological Analysis of Five Isolates of a Single Serotype of Foot-and-Mouth Disease Virus

Abstract

Some of the biochemical and serological characteristics of 5 isolates of foot-and-mouth disease virus (FMDV), serotype A, were compared. Three of the viruses were assigned to the same subtype, A22; the other 2 belong to different subtypes, A5 and A24. RNA competition hybridization and 2-dimensional electrophoresis of the oligonucleotides produced by RNase T1 showed that the 3 A22 viruses formed a group which could be distinguished from the A5 and A24 viruses. The 3 A22 viruses showed some differences by both tests. Analysis of the virus polypeptides by polyacrylamide gel electrophoresis methods also distinguished the A22 viruses as a group distinct from the A5 and A24 viruses, but small differences within the A22 group were observed using electrofocusing techniques. Serological differences were observed between the viruses using complement fixation tests and by competition radioimmunoassay with antisera obtained from guinea pigs infected with these viruses. The greatest similarity occurred between the viruses previously subtyped as A22, with A5 and A24 being distinct from the A22 group and from each other. The relationship of the biochemical and serological data is discussed.