Genetic and antigenic analysis of a recombinant foot-and-mouth disease virus

摘要

Genetic and antigenic analysis of a recombinant foot-and-mouth disease virus has been carried out in relation to the two representative isolates from the parental genotypes involved in recombination in the coat protein genes, and the vaccine strains currently being used in the country. The recombinant (IND 170/88) is divergent antigenically (r value < 0.2) and genetically (6.9-13.3% at nucleotide level and 5.2-7.4% at amino acid level) from the two vaccine strains (IND 490/97 and IND 17/77). However, it maintained antigenic closeness (r value 1.0) with one parental genotype (IND 40/00 of genotype VII) and was divergent (r value 0.35) from the other (IND 233/99 of genotype VI). The antigenic analysis in relation to the critical amino acid residues involved in virus neutralization has been discussed, but no correlation could be made between genetic divergence and antigenic relationships. This could be due to modulation of overall antigenicity of the virus by amino acid substitutions occurring at positions neighbouring the known antigenically critical residues.