A new universal flu vaccine can protect against diverse variants of both influenza A and B, according to a study from the Institute for Biomedical Sciences at Georgia State University (GSU).
Researchers from GSU designed a single universal flu vaccine candidate with key cross-protective, less variable parts of the influenza A and B viruses. The vaccine used multi-neuraminidase protein subtypes known to be antiviral drug targets and the universally conserved M2 ectodomain protein. The new universal flu vaccine was then tested on mice.
The findings were published in the journal PLOS Pathogens.
Universal flu vaccine successful on mice
The researchers found that mice vaccinated with an immune-stimulating virus-like particle, displayed multiple neuraminidase subtypes and conserved M2 portions of antigens (foreign proteins that induce immune responses). The mice were successfully protected against influenza A seasonal variants and influenza B (Yamagata and Victoria lineage) viruses containing significant antigenic variations. Additionally, the mice were protected against potential pandemic viruses (H1N1, H5N1, H3N2, H9N2, and H7N9).
Viral variants of influenza emerge when flu pathogens change their major surface hemagglutinin protein, these proteins bind themselves to the host’s receptor molecules. Continuous mutational changes in the hemagglutinin proteins can lead to severe flu disease if they escape the host immune system.
Currently, influenza vaccines are based on strain-specific immunity to hemagglutinin, this is a highly variable approach to immune protection. Annual influenza vaccination is recommended; however, the effectiveness of the vaccine is unpredictable and has been as low as 20%.
This highlights the need for an effective universal flu vaccine. Continuous changes in hemagglutinin proteins make it difficult for vaccines to stay effective year on year, therefore, influenza remains a high risk to human health across the world.
“We developed a single, universal flu vaccine entity that induced immunity to conserved M2 ectodomain and multi subtype neuraminidase proteins and was found to be effective in conferring broad cross-protection against antigenically diverse influenza A and B viruses in young and aged mice,” said Dr Sang-Moo Kang, professor at GSU’s Institute for Biomedical Sciences and senior author of the study.
New vaccine can provide broad flu protection
A novel strategy for creating a universal flu vaccine against influenza is supported by the study. The research suggests that a single construct displaying multiple cross-protective proteins can create immunity to M2 and multi-subtype neuraminidase proteins of influenza A and B viruses. As well as this, the new universal flu vaccine was found to provide broad protection against sickness and mortality in mice who were subject to a lethal flu virus.
The researchers also found that their universal flu vaccine provided broad neuraminidase inhibition in the mice. M2 ectodomain-specific antibodies and T cell immune responses were also found in the mice. Promisingly, the universal flu vaccine was found to have equal effectiveness in young and aged mice. The study is set to continue with further tests on ferrets, which have a similar respiratory system to humans.
“This study provides impactful insight into developing a universal flu vaccine inducing broad immunity against both flu A and B variants in young and aged populations,” said Dr Kang.
