Llama “nanobodies” might grant universal flu protection

Graphical depiction of a virus.

Enlarge / The flu virus,
showing the H and N proteins on its surface. (credit: CDC)

Llama antibodies are different from ours. Our antibodies are a
mix of two pairs of proteins, heavy and light, wrapped around each
other. Llamas, camels, and sharks all use only a pair of heavy
chains. Because they are smaller, they can wedge into molecular
crevices that our larger antibodies can’t access. Perhaps
that’s why scientists based at The Scripps Institute decided to
use them as a basis for flu protection.

There are four types of influenza viruses, creatively termed A,
B, C, and D. Influenzas A and B are responsible for seasonal
epidemics in humans, and influenza A is the one that causes
pandemics. Influenza A viruses are further divided into subtypes
based on two proteins on the surface of the virus: hemagglutinin
(H) and neuraminidase (N). There are 18 different hemagglutinin
subtypes and 11 different N subtypes, leading to nomenclature like
H3N1.

Current flu vaccines generate antibodies to the head of the
hemagglutinin protein, which is highly variable. This is why we
need to get a new shot every year: it ensures we make antibodies
that bind to and counteract the strain in circulation that year.
Broadly neutralizing antibodies that recognize all forms of
hemagglutinin have been made and tested, but they don’t combat
influenza B, and they don’t last for very long in our upper
airways.

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Source: FS – All – Science – News
Llama “nanobodies” might grant universal flu protection