An article I read a while back discusses a novel method of controlling flu virus infection using a protecting virus. The concept was developed for influenza type A and involves a genetically modified version of the virus that has an 80% deletion on one of the 8 RNA strands. This deletion renders the virus harmless and interferes with the ability to reproduce once inside a cell. When it is joined by another normal influenza virus, the protecting virus replicates much faster than the normal influenza virus thereby crowding it out resulting in a slowed rate of progression. This delay allows the immune system time to develop and mount an immune response.
The implications of such a cascade are that any strain of influenza that you encounter will become it's own vaccine by giving the body time to recognize the virus and develop an effective response. Thus, protection is conferred against unforeseen strains and mutations that vaccines have a lesser ability to deal with. This is especially desirable for a virus that mutates often leaving vaccines that cannot protect against all variations. In addition, by using a live infection, you are creating a better immune response than by using peptides of the viral products alone. Current research shows that protection from infection happens immediately upon administration and can even be given 24 hrs after exposure while maintaining effectiveness.
Some experiments have been done to show that by putting the protecting virus in drinking water of animals they have gained protection from various strains of influenza. From our discussions in class regarding H5N1 and the jump from birds to humans, could this be useful to impact the spread of avian flu within bird populations? Because of the protecting virus' ability to act as a vaccine to highly mutable viruses, could this be a tool to use against other infections?
This pioneering research was done by Nigel Dimmock at the
3 comments:
Very interesting!
So is the protecting virus always replicating, even in the absence of a normal influenza virus? If so what exactly is "replicating" - does it harm the host cell in anyway?
This is quite novel. Are other viral types also being made for other diseases (for example HIV)
I'm guessing that the "protecting" virus can infect but not replicate until the cell gets infected by a "real" flu, which provides the missing oomph. Then it replicated faster because it has less genetic baggage. Hard to believe, somehow.
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