Universal Flu: Treatment Created From Llama Antibodies Is a Hopeful Step
Each year epidemiologists race to determine which seasonal flu strains are most likely to infect the population. It’s an old-fashioned system. Once the strains are determined, vaccine production begins — in the United States alone, there needs to be a stockpile of 150 million injectable doses. This year, public health officials are hopeful about the strength of the makeup of the newest vaccine. That’s essential because poor epidemiological forecasting is literally the difference between life and death.
Because of this tremendous risk, scientists around the world are on the hunt for a universal flu vaccine — a treatment that doesn’t have to be tailored to each new flu season’s circulating viruses. And the hunt may soon be over. Researchers have published a new study in Science claiming that the key to this treatment could lie with a pack animal that would spit on you if it could: the llama.
In the study released Tuesday, an international team of scientists explain that their hypothetical universal flu vaccine is less of a vaccine and more of a nasal spray. Within it are antibodies, derived from llamas, that can bind to and neutralize multiple strains of the influenza virus.
“Llama antibodies have been known for some time and they have several unique properties that make them attractive for drug development,” explains study co-author Joost Kolkman, Ph.D., to Inverse. “They can bind to epitopes that are not accessible to conventional antibodies because of their small size and shape. In addition, they can be easily linked together to create multi-specific antibodies binding to different epitopes on the same or different targets.”
Kolkman, an antibody engineer at Janssen Infectious Diseases, says that this multi-specificity is the key to attaining broad coverage of highly variable pathogens like influenza strains. Antibodies are blood proteins that can combine chemically with bacteria and viruses, while epitopes are the part of an antigen molecule where antibodies can attach.
Llamas produce single-domain antibodies that are 90 percent smaller than human antibodies. Kolkman and his colleagues hypothesized that this meant llama antibodies would be able to reach parts of the flu virus that human antibodies can not. To test this idea, the team injected llamas with a vaccine containing three different influenza viruses and a viral surface protein linked to two other flu strains. They then collected the four llama antibodies that neutralized the flu strains.
These neutralizing antibodies were strung together to create a gene that acts as a sort of mega-antibody. When incorporated as a nasal spray and given to mice, it effectively latched on to 59 out of 60 flu strains and prevented the mice from becoming infected. While more testing is needed, Kolkman believes that the team’s preclinical strategy could one day help protect humans from influenza A and B infections.
“Our manuscript describes for the first time an antibody with direct neutralizing activity against both influenza A and B viruses,” Kolkman says. “None of the broadly neutralizing influenza antibodies discovered to date are capable of directly neutralizing both influenza A and B, which is essential for influenza prophylaxis.”
He cautions that it remains too early to say when this antibody nasal spray can be on humans, but the research itself is promising. While the antibodies that are a part of each annual flu shot are ineffective by the next year’s flu, this antibody strategy wouldn’t be restricted to yearly seasons. And after last year’s deadly flu season, that’s good news: 80,000 Americans died from the flu last winter, a tally that’s double what public officials typically consider a bad year.