Influenza A is a member of the orthomyxoviridae family. Along
with other influenza viruses, it causes from 3-5 million severe illnesses annually. Control of influenza epidemics rely on vaccinations
and some antivirals like Tamiflu, but due to antigenic drift, and hundreds of
strains, they have been wickedly resistant to containment. Haemagglutinin (HA)
is a glycoprotein embedded in the envelope of Influenza A, and is responsible
for receptor binding and membrane fusion. Current antivirals often target the head of
HA to prevent viral infection, but the head is highly variable which prevents
antibody effectiveness over a wide range of the Influenza A viruses, and mutates quickly.
In a new article published in Nature, researchers chose to
focus on a different part of Haemagglutinin—the stem. The stem is a more
conserved area of the glycoprotein, and antibodies that target this region may
have more cross-reactivity. A monoclonal antibody named 3E1 has previously
shown reactivity to the HA stem region, and showed promise in blocking viral infection.
In the latest research, it was confirmed that 3E1 binds to the stem of the
viral glycoprotein, and it was shown that 3E1 is effective at neutralizing a
wide range of H1N1 and H5N1 subtypes.
Modeling of the
antigen and its binding action demonstrate that 3E1 attaches to a highly
conserved region of HA with a complementarity value comparable to other
antibodies that are being investigated as weapons against Influenza A. When it
binds, it prevents a conformational change in HA, which prevents it from going
from a pre-fusion state to a fusion state, denying the virus access to the cell.
Although there is still much research to be done on this
antibody, it shows promise as a model for developing antibody-based therapies
against pandemic flus due to the lower mutation rate of the stem, and wider
range of sub strains that is can neutralize as compared to traditional
antiviral therapies.
Read the full article here:
Elisa Hofmeister ‘18
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