Flu viruses are constantly mutating and every year the seasonal flu shot is updated to keep up with the viruses that are making people sick. Readers interested in the prospect of a â€œuniversal flu vaccineâ€ may have noticed some experimental progress on that theme this week.
The reports build on findings some years ago fromÂ Emory Vaccine Center researchers led by Rafi Ahmed. Ahmedâ€™s team had showed that people infected by the 2009 H1N1 flu strain developed broadly protective antibodies, and separately, so did volunteers immunized against the H5N1 avian flu virus.
Some background: the head region of the flu virusâ€™s mushroom-like hemagglutinin protein is more variable, and more exposed to the immune system, while the stem/stalk region is less variable.
The underlying idea is: if someoneâ€™s immune system is exposed to flu viruses different enough than what it has seen before (like in the 2009 H1N1 outbreak and the H5N1 study), the antibodies to the stem region become more important and more prominent.
The NIAID team fused the flu hemagglutinin to ferritin, a platform for further protein engineering.
This week, what the researchers from NIAID (Nature Medicine) and Scripps/J&J (Science) showed is that experimental vaccines made from the stem region only can be broadly protective in several animal models. This required some protein engineering and reconstruction because chopping off the head of the hemagglutinin protein makes it fall apart.
Emory Vaccine Centerâ€™s Walter Orenstein, in comments for Genetic Experts News Service, wrote:
These are animal studies, so we are some way off for development and testing of a vaccine in humans.Â The technique is promising and a step in the right direction. Read more
Scientists at Emory and the University of Chicago have discovered that the 2009 H1N1 flu virus provides excellent antibody protection. This may be a milestone discovery in the search for a universal flu vaccine.
Researchers took blood samples from patients infected with the 2009 H1N1 strain and developed antibodies in cell culture. Some of the antibodies were broadly protective and could provide protection from the H1N1 viruses that circulated over the past 10 years in addition to the 1918 pandemic flu virus and even avian influenza or bird flu (H5N1).
The antibodies protected mice from a lethal viral dose, even 60 hours post-infection.
The research is published online in the Journal of Experimental Medicine.
Some of the antibodies stuck to the â€œstalkâ€ region, or hemagglutinin (H in H1N1) protein part of the virus. Because this part of the virus doesnâ€™t change as much as other regions, scientists have proposed to make it the basis for a vaccine that could provide broader protection. The antibodies could guide researchers in designing a vaccine that gives people long-lasting protection against a wide spectrum of flu viruses.
The paperâ€™s first author, Emory School of Medicineâ€™s Jens Wrammert, PhD, says â€œOur data shows that infection with the 2009 pandemic influenza strain could induce broadly protective antibodies that are very rarely seen after seasonal flu infections or flu shots. These findings show that these types of antibodies can be induced in humans, if the immune system has the right stimulation, and suggest that a pan-influenza vaccine might be feasible.”
Rafi Ahmed, PhD, director of the Emory Vaccine Center, and a Georgia Research Alliance Eminent Scholar, is co-senior author of the publication, along with Patrick Wilson at University of Chicago.
- See YouTube for video commentary by Dr. Ahmed
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