Strains of a common subtype of influenza virus, H3N2, have almost universally acquired a mutation that effectively blocks antibodies from binding to a key viral protein.
The mutation alters a viral protein called neuraminidase, and the researchers found in their study that this alteration paradoxically reduces the ability of flu virus to replicate in a type of human nasal cell that it normally infects. However, the researchers also found evidence that the mutation more than compensates for this deficit by setting up a physical barrier that hinders antibodies from binding to neuraminidase.
Scientists have known that it alters the flu virus's neuraminidase protein in a way that provides an attachment point, close to neuraminidase's active site, for a sugar-like molecule called a glycan. But how the presence of a glycan at that location on the neuraminidase protein improves the virus's ability to infect hosts and spread hasn't been clear.
These findings tell us that flu vaccines focusing on the hemagglutinin protein are leaving the virus openings to evolve and evade other types of immunity
Every year, influenza viruses sicken millions of people around the world, killing several hundred thousands. The diversity of flu strains and their ability to mutate rapidly—two strains infecting the same host can even swap genes—have made flu viruses an especially difficult target for vaccine designers.
Although scientists are working towards a universal vaccine that will protect long-term against most flu variants, current flu vaccines are designed to protect against only a short list of recently circulating strains. Any mutation that occurs in these circulating strains and appears to improve their ability to spread is naturally of interest to flu virologists.
The mutation alters a viral protein called neuraminidase, and the researchers found in their study that this alteration paradoxically reduces the ability of flu virus to replicate in a type of human nasal cell that it normally infects. However, the researchers also found evidence that the mutation more than compensates for this deficit by setting up a physical barrier that hinders antibodies from binding to neuraminidase.
Scientists have known that it alters the flu virus's neuraminidase protein in a way that provides an attachment point, close to neuraminidase's active site, for a sugar-like molecule called a glycan. But how the presence of a glycan at that location on the neuraminidase protein improves the virus's ability to infect hosts and spread hasn't been clear.
These findings tell us that flu vaccines focusing on the hemagglutinin protein are leaving the virus openings to evolve and evade other types of immunity
Every year, influenza viruses sicken millions of people around the world, killing several hundred thousands. The diversity of flu strains and their ability to mutate rapidly—two strains infecting the same host can even swap genes—have made flu viruses an especially difficult target for vaccine designers.
Although scientists are working towards a universal vaccine that will protect long-term against most flu variants, current flu vaccines are designed to protect against only a short list of recently circulating strains. Any mutation that occurs in these circulating strains and appears to improve their ability to spread is naturally of interest to flu virologists.
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