Llamas could play a role in finding a universal flu vaccine

Llamas could play a role in finding a universal flu vaccine

Along with soulful eyes, endearingly long necks and warm fuzzy coats, llamas have a far less appreciated feature: They make an array of immune system antibodies so they can fit into crevices on the surface of invading virus.

That feat could protect humans from the flow of water with their unpredictable and shape-shifting ways.

All, potentially, with a once-a-year puff up the nose.

In a study in Friday's edition of the journal Science, a team from the Scripps Research Institute at La Jolla and their international colleagues have taken a major step towards the long-sought goal of developing a universal vaccine against influenza.

When they are testing their intranasal formulation in mice, it is quickly conferred complete protection against a risk of human flu strains adapted to mice. Those include A viruses, as the H1N1 "swine flu" that touched off a global pandemic in 2009, and B viruses, which occur only in humans.

Against H1N1, a dose of the experimental vaccine shown at least 35 days – a span of time equivalent to more than a flu season for humans.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, offered a full-throated appreciation for the study, which received funding from the National Institutes of Health.

"From a scientific and technical standpoint, this is really a very elegant study – the highest quality of science," Fauci said. Scientists must construct vaccines that can be fatal or compromised.

Influenza is a viral scourge that kills as many as 650,000 people each year, according to the World Health Organization. To fight it, the research team borrowed techniques from immunology, microbiology, nanotechnology and genetic engineering labs around the world.

First, they are vaccinated against a number of A and B strains of influenza. Then they took blood samples to collect the antibodies produced in response.

Among them were four very small antibodies that showed the ability to destroy many strains of influenza. In a nod to their size and function, they called their creations "nanobodies."

From those multitasking little powerhouses, the researchers engineered a protein capable of squeezing into space on a virus surface that are too small for most proteins. The resulting "multidomain antibody MD3606," with its "impressive breadth and potency," could not confer protection against any strain that could possibly throw in human blood's way, the study authors said.

If the dominant strain in a given season were to change suddenly, these antibodies would be ready for the unwelcome guest. If a flu strain came out of nowhere and threatened a population with no immunity to it – the nightmare scenario of pandemic flu – this supercharged defender would recognize that flu and counter it. Ineffective – a scenario that played out last season – this package of antibodies could save the day.

But the researchers faced a key hurdle: getting the human immune system to make a super-protein even when it's weighed down by age, stress and disease.

Their solution: Do not try.

Instead, they are devoting themselves to a process of human unreliable response to vaccines. To ferry that into a host organism, they enlisted a harmless virus used by labs on gene therapy.

By splicing their designer into a viral delivery device, the scientists are only looking at the article. This "passive transfer" of antibodies gives this vaccine candidate the potential to be effective in everyone, Fauci said.

The next step is to conduct further tests in animals and clinical trials in humans, and that "will take years," he said. What does it take to get it out of season?

Scripps immunologist Ian Wilson, the study's senior author, said that the cells were "infected" by the virus delivery. "We do not really know how long this treatment would survive in humans yet," he said.

But even less-than-permanent immunity against a broad range of flu threats would help buffer people from the emergence of unexpected flu strains, Wilson said. And the rapid response of mice to the vaccine suggests that it has emerged, he added.

Ted M. Ross, who directs the University of Georgia's Center for Vaccines and Immunology, said the experimental vaccine might need to be done every year.

"This approach is similar to antivenom," Ross said. The therapeutic agent is an antibody that neutralizes the toxin. It's short-term, but it gets through the period of time where bad things could happen. "

Over time, patients who got the same time again, he said. Vaccine makers could find that by finding and including new antibodies in their formulation every few years, he suggested.

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