ABSTRACT
The highly-pathogenic EV71 strain is the primary cause of mortality in hand-foot-and-mouth disease (HFMD) associated with neurological symptoms, for which no clinically effective drugs or vaccines exist. This study aimed to construct infectious cDNA clones of the EV71 highly-pathogenic strain and the cell-culture adapted strain using a reverse genetics approach. The genomic RNAs of EV71 parent strains were used as the templates for RT-PCR amplification, and then the PCR products that overlapped the full-length genome were connected into the pBR322 vector to produce infectious clones of pEV71 (HP) and pEV71 (CCA), respectively. The results showed that the HP strain propagated much more quickly than the CCA strain. The rescued viruses derived from the infectious clones not only maintained their consistency with their parent strains in terms of genomic sequences, but also retained their respective biological phenotypes. This research will contribute to our understanding of EV71 pathogenesis and the development of novel vaccines against HFMD.
Subject(s)
Animals , Humans , Chlorocebus aethiops , DNA, Complementary , Enterovirus A, Human , Genetics , Virulence , Hand, Foot and Mouth Disease , Virology , Phylogeny , Vero Cells , Virus CultivationABSTRACT
<p><b>OBJECTIVE</b>To determine the main genotype of hepatitis B virus (HBV) detected from Tibetans in China and provide basic data for hepatitis control and prevention.</p><p><b>METHODS</b>The S gene and C gene were amplified by PCR from the sera of HBsAg positive Tibetans. After sequencing, the gene sequences were analyzed and the phylogenetic trees were drawn by the software MEGA3.</p><p><b>RESULTS</b>In trees based on S gene, the sequences of most samples clustered at genotype D, while in trees based on C gene, the sequences of all samples clustered at genotype C.</p><p><b>CONCLUSION</b>The dominant genotype of HBV detected from Tibetans in China is a C/D hybrid.</p>