A new study by researchers from Georgia State University shows that a ground-breaking universal flu vaccine can confer protection against varied influenza A virus strains and subtypes in both young and old populations.
A Person With The Flu
The new vaccine, developed by scientists at Georgia State University’s Institute for Biomedical Sciences, is called the M2e-stalk protein vaccine.
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Results from the study show that inoculation with this vaccine promoted extensive protection against various strains and subtypes of influenza virus A strains in mice through universal vaccine-medicated immunity.
The research team published their findings in the journal npj Vaccines.
Reduced vaccine efficacy
It has proven tough to effectively deal with influenza A virus infections, especially those caused by the H3N2 subtype.
The efficacy of vaccination against influenza A H3N2 variant viruses stood at just around 33 percent during the previous decade, as said by researchers. It was as low as six percent in the course of the 2014-2015 flu season.
H3N2 viruses tend to have a more severe impact, compared to most other influenza virus strains. Mutations of its variants continue to occur, with these usually making them more dangerous.
Concerns were raised over possible pandemics as a result of an outbreak of another subtype known as H7N9.
There is an urgent need for more reliable vaccines to combat influenza A virus infections. Researchers have, however, found it difficult to come up with these. A major reason this has been challenging is that the viruses’ head section is always changing.
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In comparison to the H1N1 virus subtype, researchers say H3N2 poses a greater challenge. Stalk mutations are common in the circulating strains of the latter subtype. Also, the viruses’ stalk proteins have an unstable structure.
As per scientists, these obstacles have made it hard to develop H3 stalk-based vaccines that work very well.
A novel approach
In this research, the team genetically linked highly conserved extracellular domain of matrix 2 (M2e) and stalk protein of H3N2 viruses to create its novel universal flu vaccine. These preserved sections of the virus remained somewhat unchanged over time.
Researchers found that their universal flu vaccine spawned M2e and stalk-specific Immunoglobulin G (IgG) antibodies. They said these protective proteins could detect influenza viral antigens that were antigenically distinct on virus particles and infected cell surfaces.
In mice, the M2e-stalk protein vaccine spurred cellular T cell immunity. It also led to efficient lung influenza viral clearance.
“The M2e-stalk protein, for the first time, could be easily produced in bacterial cell cultures at high yields and was found to confer protection against heterologous and heterosubtypic cross-group subtype viruses (H1N1, H5N1, H9N2, H3N2, and H7N9) at similar levels in adult and aged mice,” said senior study author Dr. Sang-Moo Kang, a professor at Georgia State’s Institute for Biomedical Sciences.
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Findings in this study show that M2e-stalk proteins offer a low-cost means of making an effective universal flu vaccine for both young and old, researchers said.
References
A chimeric thermostable M2e and H3 stalk-based universal influenza A virus vaccine
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