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A combination of llama and human antibodies administered by a virus protects against almost all types of influenza. The experiment was performed on mice and shows all the complexity of the fight against the flu virus, but also a lot of human ingenuity. While much remains to be done for his essay on the man and many problems may arise by then, this new strategy suggests the promise of a universal flu shot.
The flu virus is one of the most elusive of all. In addition to the hundreds of types, subtypes and strains identified, their mutation rate (and thus escape the radar of the immune system) is very high. Much of this virus's ability to escape is due to a substance that, like flowers, springs from its surface in clusters of three. This is what is called haemagglutinin (HA), a protein that stands out in a double sense: it is responsible for fixing the virus on the infected cell, but that is also the most exposed part and at which the defenses react first.
Current vaccines target haemagglutinin, especially its three heads. But this part is also the most mutable. In 1968, an influenza epidemic broke out in Hong Kong and degenerated into the third pandemic of the century. In one year, one million people have died. Its huge impact is due in large part to the fact that human defenses are not formed. The virus, H3N2, exhibited a variation in the HA head that delayed its detection by antibodies. Since the middle of the last century, the H3N2 influenza virus has undergone 75 changes in HA proteins. This shows why the vaccine is also different each year and can only be designed for one or two of the dominant strains each season.
A large group of researchers has developed a complex and very different strategy for controlling the disease. In practice, all rodents survived lethal doses of various types of influenza and the vaccination lasted for months.
"Camelid antibodies have been known for some time and have several unique properties that make them attractive to humans – drug development," says Joost Kolkman, researcher in the field of infectious diseases and vaccines and co-author of the study.
In 1989, then student Raymond Hamers was found in the camel's immune system. and the water buffalo, a type of antibody previously unknown. "They can bind to sites that are inaccessible to clbadical antibodies because of their shape and small size," says Kolkman. They are about 10 times smaller than human antibodies.
"They can easily bind to create multispecific antibodies that bind to different (virus) points of the same or different targets." Joost Kolkman. Scientist
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