In the research, published in Science Translational Medicine, delivering a gene into the nasal passages of animals provided protection against many strains of flu. The gene expresses an antibody that was shown to prevent the animals from developing the flu when exposed to the virus.
If the technique is shown to be safe and effective in humans, this approach could be used to protect people in the event of a flu pandemic. It may also help to ward off viruses that originate in animals but can be spread to humans.
Dr James Wilson, who led the study, said: 'The experiments described in our paper provide critical proof-of-concept in animals about a technology platform that can be deployed in the setting of virtually any pandemic or biological attack for which a neutralising antibody exists or can be easily isolated'.
The team, from the University of Pennsylvania, used a virus vector to deliver the gene to cells lining the noses of mice and ferrets. These animals were exposed to lethal doses of the H1N1 strains responsible for the 1918 and 2009 pandemics, as well the highly pathogenic avian H5N1 strain that scientists fear could cause a pandemic in the future (reported in BioNews 662).
Treatment gave mice complete protection and reduced virus replication considerably. The approach was also effective in ferrets, which are a more authentic model of human flu infection.
Currently, the most effective method of combating flu infection is vaccination. However, vaccine production is a time-consuming process and the delay in creating and distributing a vaccine for a novel pandemic strain could have devastating consequences.
Wilson's approach of rapidly establishing protection against a wide range of flu strains may be a useful alternative. 'The technology isn't trying to stimulate the immune system to generate antibodies ', Dr Wilson told the Wall Street Journal. 'It simply engineers the cells to make antibodies'.
However, unlike vaccination, where the body's immune system retains the ability to produce antibodies for many years, antibody production has so far only lasted for about three months. The team are now investigating how antibody production can be maintained for six months.