A new universal flu vaccine protects against diverse variants of both influenza A and B viruses in mice, according to a new study published in the journal PLOS Pathogens.
The researchers designed a single, universal influenza vaccine candidate with key cross-protective, less variable parts of the influenza A and B viruses: multi-neuraminidase protein subtypes known to be major antiviral drug targets and the universally conserved M2 ectodomain protein.
The researchers, from the Institute for Biomedical Sciences at Georgia State University, report that mice vaccinated with an immune stimulating virus-like particle displaying multiple neuraminidase subtypes and conserved M2 portions of antigens were protected against influenza A seasonal variants and pandemic potential viruses (H1N1, H5N1, H3N2, H9N2 and H7N9) and influenza B (Yamagata and Victoria lineage) viruses containing substantial antigenic variations.
Viral variants emerge when flu pathogens change their major surface haemagglutinin protein that binds to host receptor molecules. Continuous mutational changes in the flu haemagglutinin proteins result in immune escape and sever disease.
Current influenza vaccines are based on strain-specific immunity to haemagglutinin, a highly variable target of immune protection. The effectiveness of the seasonal vaccine is unpredictable and could be below 20% because of continuous changes in haemagglutinin proteins. Influenza therefore remains a significant risk to human health worldwide.
“We developed a single, universal 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 Professor Sang-Moo Kang, senior author of the study. “This study provides impactful insight into developing a universal influenza vaccine inducing broad immunity against both flu A and B variants in young and aged populations.”
This study supports a novel strategy for creating a universal vaccine against influenza A and B viruses. A single construct displaying multiple cross protective proteins has the capacity to induce immunity to M2 and multi-subtype neuraminidase proteins of influenza A and B viruses, as well as offer broad cross protection against sickness and mortality under lethal flu virus challenges in mice, according to the study.
Vaccinating mice with this universal vaccine candidate induced broad neuraminidase inhibition, M2 ectodomain specific antibodies and T cell immune responses. Comparable cross protection was induced in aged mice.
The study warrants further testing of this unique, universal va ccine candidate in ferrets, which have similar respiratory tracts to humans.
Source: Georgia State University
