[Complete genomic sequence analysis on human enterovirus 71 strain in Guangzhou, in 2008 and 2010]

To study the genomic genotypes and variation of human enterovirus 71 (EV71) infected infants in Guangzhou city, in 2008 and 2010.

Primers were designed on the basis of the genomic sequence of EV71 SHZH03 strain (AY465356) in the GenBank, and EV71 genome amplified by RT-PCR. PCR-products were directly sequenced and the genomic nucleotide sequences were analyzed with the programs of Clustal W/X, DNASTAR and MEGA 4.1.

9 strains of EV71 genome appeared to be 7405 bp in length. The genomic sequences of EV71 Guangzhou strains were compared with those of EV71 in GenBank, which revealed that the homology with EV71 genotype C4a Fuyang strains ranged between 98% - 99%. Homology with genotype C4b were 92% - 94%, with genotypes C1, C2, C3 as 82% - 83%, with genotypes B3, B4, B5 as 81% - 83% and the homology with genotype A was 80%. When compared the VP1 genes of EV71 Guangzhou strains with genotypes A, B, C virus, we revealed that the highest homology was also with genotype C4a. When compared the VP1 amino acid sequences of EV71 Guangzhou strains with genotype A, B, C virus by Clustal W program, the results revealed that the amino acid residue Q at position 22 in VP1 gene was transformed to H, while 213 (S→T) and 1764 (V→I) mutations in polyprotein were discovered.

Data from the sequences and phylogenetics analysis on those Guangzhou strains in 2008 and 2010 revealed that those isolates belong to genotype C4a, with the homology with Fuyang strains as 98%-99%. Mutation of amino acid residue H at position 22 in VP1 gene was discovered and the neutralizing antibody of EV71 might have been conversed by this residue. 213 (S→T) and 1764 (V→I) mutations in polyprotein were also discovered.