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Gravel C.,Biologics | Elmgren C.,Canadian Food Inspection Agency | Muralidharan A.,Biologics | Muralidharan A.,University of Ottawa | And 12 more authors.
Vaccine | Year: 2015

H7N9 is a newly emerged avian influenza virus with a relatively high mortality rate in humans. At this time, there is no licensed vaccine for human protection. Development of analytical tools for H7N9 vaccine could facilitate vaccine development. Here, a universally conserved epitope in all H7 hemagglutinin (HA) sequences was identified through comprehensive bioinformatics analyses. The peptide epitope, RSGSSFYAEMK, (aa positions 149 to 159), is located on the head of the HA molecule. Antibodies generated against this universal H7 epitope were remarkably specific against H7 viral sequence with no detectable cross-reactivity to other HA subtypes. A new immunoblotting assay based on the universal H7 antibody was developed and compared with the traditional single radial immunodiffusion assay (SRID) for potency analyses of candidate H7N9 vaccines. This new assay was more sensitive and rapid compared to SRID. In addition to statistically acceptable precision and reproducibility, the new assay differs from many other alternative potency assays for influenza vaccine in that it is potentially stability-indicating, which is an important requirement for industry vaccine stability studies analyses. Furthermore, the robustness of this new assay was demonstrated by the quantitative determination of HA content in four H7N9 vaccines (split or inactivated) from different manufacturers. © 2015.

Shi D.,National Institutes for Food and Drug Control | Shen S.,National Institutes for Food and Drug Control | Fan X.,National Institutes for Food and Drug Control | Fan X.,Collaborating Center for Standardization and Evaluation of Biologicals | And 12 more authors.
PLoS ONE | Year: 2015

A novel avian influenza A H7N9-subtype virus emerged in China in 2013 and threatened global public health. Commercial kits that specifically detect avian influenza A (H7N9) virus RNA are urgently required to prepare for the emergence and potential pandemic of this novel influenza virus. The safety and effectiveness of three commercial molecular diagnostic assays were evaluated using a quality-control panel and clinical specimens collected from over 90 patients with confirmed avian influenza A (H7N9) virus infections. The analytical performance evaluation showed that diverse influenza H7N9 viruses can be detected with high within- and between-lot reproducibility and without cross-reactivity to other influenza viruses (H1N1 pdm09, seasonal H1N1, H3N2, H5N1 and influenza B). The detection limit of all the commercial assays was 2.83 Log10 copies/μl [0.7 Log10T-CID50/mL of avian influenza A (H7N9) virus strain A/Zhejiang/DTID-ZJU01/2013], which is comparable to the method recommended by the World Health Organization (WHO). In addition, using a WHO-Chinese National Influenza Center (CNIC) method as a reference for clinical evaluation, positive agreement of more than 98% was determined for all of the commercial kits, while negative agreement of more than 99% was observed. In conclusion, our findings provide comprehensive evidence for the high performance of three commercial diagnostic assays and suggest the application of these assays as rapid and effective diagnostic tools for avian influenza A (H7N9) virus in the routine clinical practice of medical laboratories. © 2015 Shi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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