For years now, researchers have been searching for a universal vaccine for influenza. The flu kills thousands of people every year in the United States alone and approximately 300,000 to 650,000 people worldwide every year.
One of the most promising candidates for a universal flu vaccine that would protect against entire families of flu viruses was described today in the journal Science. The vaccine is based on antibodies created in the South American llama, a relative of the camel family.
Flu viruses and vaccines
Even though flu vaccines can prevent many viral infections each year, they don’t prevent all of them. This is simply because there are so many different strains of flu viruses. Added to this is the difficulty in predicting which strain of the flu virus will be the most prevalent in any given year.
That’s why a new batch of vaccine is made up every year, and because it is a bit of a guessing game, sometimes, the vaccine may not work well. At best, flu vaccines have a 60 percent efficacy at reducing someone’s risk of becoming ill. The common cold virus is even worse when you look at the multitude of strains and this is why there is no vaccine for a cold.
A universal vaccine for the flu would put an end to the yearly guessing game of trying to figure out which flu strain was going to strike – giving us a vaccine that would cover a whole range of influenza strains. A team of researchers from the Scripps Research Institute in La Jolla, California and their international colleagues has made a major advancement to developing that universal vaccine.
Llama antibodies and the flu virus
To come up with their product, the researchers borrowed from a trove of new techniques in immunology, microbiology, nanotechnology, and genetic engineering from labs around the world. First, they vaccinated llamas against a number of A and B strains of influenza.
Then, after an appropriate length of time, they took blood samples to collect the antibodies the llamas produced in response to the flu viruses. The team found four unique and very small antibodies that showed an ability to destroy many of the strains of influenza. The team gave these small antibodies the name “nanobodies.”
The team then used the nanobodies to engineer a single protein capable of squeezing into spaces on a virus’ surface that are too small for most proteins. The resulting “multidomain antibody MD3606,” with its “impressive breadth and potency,” could confer protection against pretty much any strain of flu that nature could throw in humankind’s way, the study authors said.
The “nanobodies” worked well at attaching to a wide variety of antigens – so well that they latched on to 59 out of 60 flu strains, preventing them from multiplying. According to the study, “this kind of strain coverage is simply unprecedented and what’s more, these antibodies are stable and can be more easily produced than other types of antibodies.”
“[Our approach] could potentially be used as a preventive treatment from year to year and protect against both seasonal flu as well as potential pandemics, such as bird flu,” said Ian Wilson, a biochemist from Scripps Research who co-led the project.
there is still a long way to go before we might see a universal vaccine made from llama antibodies. Human clinical trials will have to be done, and right now, we don’t really know if the llama antibodies will be identified as foreign by our immune system, potentially causing some nasty reactions.
