Real-time PCR assay for rapid differentiation of env-based genotypes of feline leukemia virus

[Abstract] The envelope protein plays an essential role in the pathogenesis of feline leukemia virus (FeLV). Three categories of genotypes have been identified according to the sequence of the envelope gene (env). The relationship between env-based genotype and viral pathogenicity remains to be investigated. However, this effort is hampered by the fact that sequencing and phylogenetic analysis of env are expensive and time-consuming. In this study, we identified single-nucleotide polymorphisms (SNPs) that are located in the long terminal repeat but linked to env-based genotypes (G), I and III. Our real-time PCR assay included a primer containing the SNP sites and detected GI proviruses but not GIII proviruses. It will help rapid differentiation of the env-based genotypes of FeLV field isolates.