ABSTRACT
Objective To analyze the genetic characteristics of the hemagglutinin （HA) and neuraminidase （NA) genes of influenza B viruses isolated in Yancheng City from 2015 to 2017. Methods The throat swab specimens of influenza-like illness( ILI) from sentinel surveillance hospital and outbreak sites were collected and sent to Yancheng CDC for virus nucleic acids and virus isolation testing. After validation with serological tests, eighteen strains of influenza B virus isolates were selected to amplify their HA1 and NA genes through RT-PCR assay. Their molecular characteristics of the obtained viral HA1 and NA gene sequences were analyzed using bioinformation software from three aspects, including nucleic acid level, amino acid level and molecular evolution level. Results Basically, the clustering relationships and the branche patterns between HA1 and NA genes from the 18 Yancheng influenza B virus strains were similar. The Yamagata lineage strains in 2015 were distributed in the Yamagata Clade 3 branch, belonging to Phuket/3073 strains. The Victoria lineage strains in 2016-2017 were distributed in the Victoria Clade 1A branch, belonging to Brisbane/60 strains. D196N substitution was detected on HA1 protein in all of Yamagata lineage strains at 190-helix epitope; Amino acid substitutions of victoria lineage strains involved two antigenic epitopes, 117 and 129 sites of 120-loop epitope and 197 and 199 sites of 190-helix epitope. No Intra-lineage or inter-lineage rearrangements occurred in Yancheng strains. Eighteen influenza B strains had no mutations in catalytic residues and drug resistant sites of NA genes. Conclusion The Yamagata strains well matched with vaccine strain B/Phuket/3073/2013. The HA1 and NA genes of victoria lineage strains circulated in Yancheng City during 2016 to 2017 are changing gradually. The accumulation of these mutations will result in antigenic drift of victoria lineage strains and increase the mismatch of the IFV field stains with the available vaccine strains, which may reduce the protective effect of flu vaccine.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of RYBP gene on sensitivity of HL-60 cells to chemotherapy drugs by using RNA interference.</p><p><b>METHODS</b>Plasmid expressing RYBP specific shRNA was constructed and then was used to establish the RYBP knockdown stable HL-60 cell line. Q-PCR and Western blot were used to confirm the efficacy of RYBP gene silencing at mRNA and protein level respectively; then the DNA ladder and Annexin V labeled flow cytometry were used to detect cell apoptosis; CCK-8 was used detect the sensitivity of HL-60 cells to the chemotherapeutic drug cytarabine or daunorubicin.</p><p><b>RESULTS</b>The lentiviral-RYBP-shRNA vector was succesfully and effectively inhibit the expression of RYBP at mRNA and protein in HL-60 cells. It was found that without chemotherapy drug treatment the apoptosis rate of RYBP shRNA group was lower than that of the empty vector control group (NC group). When treated with cytarabine, the apoptosis rate and inhibitive rate of RYBP shRNA group were lower than those of NC group. Besides, when treated with daunorubicin, the apoptosis rate of RYBP shRNA group was lower than that of NC group, while the inhibitive rate had no significant difference.</p><p><b>CONCLUSIONS</b>RYBP gene silencing can inhibitive the apoptosis of HL-60 cells and significantly reduce the sensitivity to cytarabine, but this gene silencing can't affect the sensitivity to daunorubicin.</p>