In 2008, the G1P[8] strains from Pune were distributed into G1-Lineage 1, P[8]-Lineage 3 (12/13, 92.3%) and G1-Lineage 1, P[8]-Lineage 4 (1/13, 7.7%). Phylogenetic analysis of the G1P[8] strains from other cities in India (Fig. 1(A) and (B)) revealed circulation of the same subgenotypic lineages as in Pune. All G1P[8] strains from Kolkata (8/8, 2008–2009) and Delhi (3/3, 2000s) clustered into G1-Lineage 1, P[8]-Lineage 3. The G1P[8] strains from Manipur (2006–2007) Rigosertib mouse were distributed into G1-Lineage 1, P[8]-Lineage 3 (2/4) and G1-Lineage 1, P[8]-Lineage 4 (2/4). The Rotarix vaccine strain, 89-12,

clustered into G1-Lineage 2, P[8]-Lineage 1. The WI79-9 (G1) Cyclopamine mouse strain of RotaTeq vaccine was placed in G1-Lineage 3 while the WI79-4 (P[8]) strain was classified in P[8]-Lineage

2 (Fig. 1(A) and (B)). The G1-Lineage 1 strains showed 92.8–95.2% nucleotide and 92.9–95.4% amino acid identity with the Lineage 2 of G1 Rotarix vaccine strain and 89.9–92.0% nucleotide and 92.0–94.4% amino acid identity with the Lineage 3 of the G1 strain in RotaTeq vaccine. The G1-Lineage 2 strains were closer to the Rotarix VP7 of the same lineage (97.3–97.5% nucleotide and 97.2–97.5% amino acid identity) than to the RotaTeq VP7 of Lineage 3 (92.1–92.2% nucleotide and 94.4–94.8% amino acid identity). The VP8* of the P[8]-Lineage 3 strains were more similar to the RotaTeq P[8] (92.3–93.9% nucleotide and 92.9–95.8% amino acid identity) than to Rotarix

VP8* (89.5–91.4% nucleotide and 90.8-93.3% amino acid identity). The divergent P[8]-Lineage 4 strains showed lower identities with both the vaccine strains (Table 2). Both P[8] lineages Resminostat showed higher amino acid divergence in VP8* region than in VP5* region (Table 2). The rotavirus VP7 protein consists of two antigenic epitopes: 7-1 (7-1a and 7-1b) and 7-2 encompassing 29 amino acid residues [30]. The G1-Lineage 1 strains from Pune showed 3–6 amino acid differences with the G1-Lineage 2 strain of Rotarix and 5–8 amino acid differences with the G1-Lineage 3 strain of RotaTeq vaccine (Table 3). The majority (92.1–100%) of the G1-Lineage 1 strains showed three and one amino acid differences, respectively, in epitopes 7-1a (N94S, S123N, K291R) and 7-2 (M217T/I) in comparison with both vaccine strains. All amino acid differences were common to the G1-Lineage 1 strains of both periods (1992–1993 and 2006–2008) with the exception of the substitution L148F in epitope 7-2 that was restricted to seven strains from the years 2006–2008. In addition, all G1-Lineage 1 strains had the substitutions D97E (epitope 7-1a) and S147N (epitope 7-2) when compared to the G1 strain of RotaTeq vaccine. Strain specific differences were noted at amino acid positions 125, 129 (epitope 7-1a), 212, 213 (epitope 7-1b) and 221 (epitope 7-2) in a few (1–3) of the G1-Lineage 1 strains on comparison with both vaccine strains.