The Protective Role of TLR3 and TLR9 Ligands in Human Pharyngeal Epithelial Cells Infected with Influenza A Virus

In this study we aim to extensively investigate the anti-influenza virus immune responses in human pharyngeal epithelial cell line (Hep-2) and evaluate the protective role of Toll-like receptor (TLR) ligands in seasonal influenza A H1N1 (sH1N1) infections in vitro. We first investigated the expression of the TLRs and cytokines genes in resting and sH1N1 infected Hep-2 cells. Clear expressions of TLR3, TLR9, interleukin (IL)-6, tumour necrosis factor (TNF)-alpha and interferon (IFN)-beta were detected in resting Hep-2 cells. After sH1N1 infection, a ten-fold of TLR3 and TLR9 were elicited. Concomitant with the TLRs activation, transcriptional expression of IL-6, TNF-alpha and IFN-beta were significantly induced in sH1N1-infected cells. Pre-treatment of cells with poly I:C (an analog of viral double-stranded RNA) and CpG-ODN (a CpG-motif containing oligodeoxydinucleotide) resulted in a strong reduction of viral and cytokines mRNA expression. The results presented indicated the innate immune response activation in Hep-2 cells and affirm the antiviral role of Poly I:C and CpG-ODN in the protection against seasonal influenza A viruses.

Selection of sentinel sites for death surveillance,using cluster or unequal probability sampling / 中华流行病学杂志

To compare the sampling errors from cluster or unequal probability sampling designs and to adopt the unequal probability sampling method to be used for death surveillance.Taking 107 areas from the county level in Shaanxi province as the sampling frame,a set of samples are drawn by equal probability cluster sampling and unequal probability designs methodologies.Sampling error and effect of each design are estimated according to their complex sample plans.Both the sampling errors depend on the sampling plan and the errors of equal probability in stratified cluster sampling appeares to be less than simple cluster sampling.The design effects of unequal probability stratified cluster sampling,such as πPS design,are slightly lower than those of equal probability stratified cluster sampling,but the unequal probability stratified cluster sampling can cover a wider scope of monitoring population.Conclusions:Results from the analysis of sampling data can not be conducted without consideration of the sampling plan when the sampling frame is finite and a given sampling plan and parameters,such as sampling proportion and population weights,are assigned in advance.Unequal probability cluster sampling designs seems to be more appropriate in selecting the national death surveillance sites since more available monitoring data can be obtained and having more weight in estimating the mortality for the whole province or the municipality to be selected.