Navigation Links
Cleverly designed vaccine blocks H5 avian influenza in models
Date:3/25/2013

WASHINGTON, DC March 25, 2013 Until now most experimental vaccines against the highly lethal H5N1 avian influenza virus have lacked effectiveness. But a new vaccine has proven highly effective against the virus when tested in both mice and ferrets. It is also effective against the H9 subtype of avian influenza. The research is published online ahead of print in the Journal of Virology.

The strength of the new vaccine is that it uses attenuated, rather than "killed" virus. (Killed viruses are broken apart with chemicals or heat, and they are used because they are safer than attenuated viruses.) Killed virus vaccines against avian influenza are injected into the bloodstream, whereas this vaccine is given via nasal spray, thus mimicking the natural infection process, stimulating a stronger immune response.

The danger of current attenuated virus vaccines is that they might exchange dangerous genetic material with garden variety influenza viruses of the sort that strike annually, potentially rendering a lethal but very hard to transmit influenza virus, such as H5, easily transmissible among humans. To mitigate those dangers, the study authors, led by Daniel Perez of the University of Maryland, came up with an ingenious design. Influenza viruses carry their genetic material in eight "segments," explains coauthor and University of Maryland colleague Troy Sutton. When viruses reassort, they exchange segments. But each segment is unique, all eight are needed, and the viruses are unfit if they contain more than eight segments.

The vaccine is based on an attenuated version of the H9 virus, with an H5 gene added into one of the H9 virus' segments, to confer immunity to the H5 virus. Segment 8, which is composed of the so-called NS1 and NS2 genes, was split apart, and the NS2 gene was moved into segment 2, adjacent to the polymerase gene, which copies the virus' genetic material during replication. Placing NS2 next to the polymerase gene slowed its function, interfering with the virus' replication. That makes the vaccine safer.

The next step was to engineer the H5 gene into the vaccine. It was inserted into segment 8, where the NS2 gene had been.

Another aspect of the new vaccine's design makes it safer still, by rendering successful reassortment less likely. Both NS1 and NS2 are needed for viral replication. Since the two genes are now separated into different segments, any reassortment will have to include both segments, instead of just segment 8, in order for a reassortant virus to be viable. This greatly reduced the probability of successful reassortment.

The World Health Organization (WHO) recognizes avian influenza subtypes H5, H7, and H9 as potential pandemic viruses, because they all have in rare instances infected humans, and because they circulate in wild birds. Single reassortants could be sufficient to breach the species barrier, and since they do not circulate among us, we lack any immunity. Moreover, H5 is unusually lethal, having killed roughly half of those few it is confirmed to have infected.


'/>"/>

Contact: Garth Hogan
ghogan@asmusa.org
202-942-9389
American Society for Microbiology
Source:Eurekalert

Related biology news :

1. A new type of data papers designed to publish online interactive keys identifying biodiversity
2. Faster, cheaper gas and liquid separation using custom designed and built mesoscopic structures
3. MIT-designed cooler preserves tuberculosis drugs, records doses
4. Portable diagnostics designed to be shaken, not stirred
5. Research is ensuring stormwater systems are designed for the future
6. HPV vaccine trends point to failures in patient education, vaccine programs
7. Cancer vaccines self-sabotage, channel immune attack to injection site
8. Human trials for Streptococcus A vaccine
9. Novel aptamer boosts T cell-based immune response to therapeutic vaccines
10. Designer bacteria may lead to better vaccines
11. UMMS experts seek better flu vaccines
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/9/2017)... -- The biomass boiler market report by Transparency Market ... globally in terms of revenue (US$ Mn) based on ... biomass boilers has been segmented on the basis of ... market based on feedstock type, has been segmented into ... crops, urban residues, and others. On the basis of ...
(Date:2/8/2017)... AWRE ), a leading supplier of biometrics software ... year ended December 31, 2016. Revenue for ... $6.9 million in the same quarter last year. Operating income ... to $2.6 million in the fourth quarter of 2015. Net ... or $0.02 per diluted share, which compares to $1.8 million, ...
(Date:2/8/2017)... The biometrics market has reached a ... organizations, desires to better authenticate or identify users ... challenge questions), biometrics is quickly working its way ... is driven by use cases, though there traditionally ... uses cases, with consumer-facing use cases encompassing authentication, ...
Breaking Biology News(10 mins):
(Date:2/22/2017)... ... February 22, 2017 , ... Pharma and biotech ... as European director. Operating from Pennside’s Zurich headquarters, Pennside Partners, GmbH, Mr. Perkins ... Pennside after more than a decade with leading market research firm, GfK. He ...
(Date:2/21/2017)... (PRWEB) , ... February 21, 2017 , ... ... healthcare organizations to build connected digital health applications, announced a partnership with Redox, ... users to seamlessly connect to many clinical systems while keeping data secure in ...
(Date:2/21/2017)... ... February 21, 2017 , ... ... its $200M operational capacity with its strategic internal leadership to provide clients ... quality and operational management. With office locations in North Carolina, Massachusetts, ...
(Date:2/21/2017)... --  Logicalis Healthcare Solutions , the healthcare-focused practice within ... provider ( www.us.logicalis.com ), today announced a new service ... service will help hospital CIOs make the best use ... and other clinicians immediate access to a pool of ... hospital IT staff to focus on broader issues such ...
Breaking Biology Technology: