Volume 6, Issue 3, June Issue - 2018, Pages:509-515
Authors: Neelam Tomar, Veena Sharma, Jeny K John, Menaka Sethi, Pradeep K. Ray, Rahul Singh Arya, Tareni Das, K. Dhama, G. Saikumar
Abstract: Majority of live attenuated vaccine against classical swine fever virus (CSFV) including HCLV/India are derived from Chinese vaccine strain, C–strain which is genogroup 1 virus. Presently genotype 2 viruses are predominantly circulating in Indian field. Therefore the present study was carried out to find out the efficacy/failure of ongoing vaccine by whole genome sequencing and analysis. The whole genome sequences of Indian classical swine fever virus isolate CSFV-UP-BD-SKN-11 (SKN-11) (Accession no. KC533776) was done in 11 overlapping fragments. SKN-11 composed of a 373 nucleotide (nt) 5'NTR, an 11,697-nt open reading frame (ORF) encoding a polyprotein of 3,898 amino acids (AAs), and a 227-nt 3'-NTR with total length of genome 12297 nts. SKN-11 strain belongs to the genotype 2.2 which is dominantly circulating in Indian field. Based on amino acid sequence of B-cell epitopes, T-cell epitopes and conformational residues there was a remarkable antigenic variation between SKN-11 (genotype 2.2) and the currently using vaccine strains, HCLV/India and C-strain (genotype 1). Furthermore, AA at position L889Q showed an extremity change from hydrophilic to hydrophobic, which may alter the antigenicity and virulence of CSFV. Close antigenic relationship was also observed with Chinese strains especially Strain-39. The vaccination programs without genotype change can resulted in alterations in viral pathogenicity. These findings may contribute to further understanding the phylogeny and antigenic variation in CSFV and development of a more effective vaccine.