FLU NEWS SCAN: Versatile flu antibodies, H9 reassortants in pigs

Aug 9, 2012

Study: Antibodies offer broad influenza B protection
American and Dutch scientists say they have found three antibodies that protect mice against both lineages of influenza B, and one of the three protects mice from both A and B viruses, an apparent global first. The discovery may lead to the development of a drug that could be effective against severe flu infections and may help in the quest for a universal flu vaccine, the scientists say in their report today in Science. The study was conducted by Scripps Research Institute in California and Crucell Vaccine Institute in the Netherlands. The Crucell team gathered a large collection of flu antibodies from volunteers who had received a seasonal flu vaccine and then screened them for antibodies that could bind to a wide range of type B strains, according to a Scripps press release. Three of the antibodies they found, called CR8033, CR8071, and CR9114, protected mice against normally lethal doses of viruses from the two type B lineages. In addition, CR9114 protected mice against influenza A/H1N1 and A/H3N2 viruses. "It's the only one in the world that we know of that has been found to do this," said Ian A. Wilson, PhD, of Scripps, one of the authors. The researchers determined that CR9114 binds to a site on the stem of the hemagglutinin protein that is much the same (highly conserved) in type A and type B viruses. This site, or epitope, will now be studied extensively as a target for vaccines and therapies, the release states. The scientists found that the other two antibodies bind to highly conserved sites on the hemagglutinin head.
Aug 9 Science abstract
Aug 9 Scripps news release
Jul 29, 2011, CIDRAP News story on broadly protective influenza A antibody

Pandemic H1N1 genes boost H9 virulence and transmission in pigs
In the latest research study exploring the pandemic potential of H9 avian flu viruses, US and Chinese investigators tested H9 reassortants containing genes from the 2009 H1N1 virus (pH1N1) in pigs and chickens and found that the combination enhanced replication and transmissibility in pigs, a sign that similar viruses that emerge in swine could pose health threats for humans. The group's findings appeared yesterday in the Journal of General Virology. Their work follows studies in 2011 that showed similar findings in mice and ferrets and was designed to assess if the same would occur in two natural hosts of H9 viruses, chickens and pigs. Using reverse genetics, they generated an H9N1 and H9N2 reassortant viruses with pH1N1 genes. They then observed how they replicated in different cell lines and compared their virulent and transmissibility with the parent H9 viruses. The parent and reassortant H9N2 transmitted to chickens, but not the H9N1 reassortant. In pigs, the H9N2 parent didn't transmit to pigs, but both H9 reassortants replicated and transmitted efficiently, similar to pH1N1. The H9N1 reassortant in pigs was shed longer, cleared later, and was transmitted more efficiently compared with the H9N2 version. The authors conclude that the new and earlier findings highlight the importance of continued surveillance of flu strains in pigs, especially in areas such as Asia where H9N2 viruses have been known to infect them.
Aug 8 J Gen Virol abstract

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