A new universal flu vaccine protects against influenza B viruses, providing broad protection against different strains and improved immune protection, according to a new study by researchers at Georgia State University’s Institute of Biomedical Sciences.
A double-layer protein nanoparticle vaccine constructed with a stabilized part of the influenza virus stem (hemagglutinin (HA)) elicited broad reactive immune responses and provided robust and sustained cross-immune protection against influenza B strains of both lineages. The results are published in the journal Biomaterials.
Influenza epidemics are a serious threat to public health, and influenza B has coincided with several serious influenza outbreaks. About a quarter of clinical cases of infection each year are caused by influenza B viruses. Influenza B viruses are sometimes the dominant strains circulating during flu seasons, such as the 2019-2020 flu season. in the US, when influenza B caused more than 50 percent of infections.
Influenza B has two lineages that are genetically distinct and cause different immune responses. Seasonal influenza vaccines are being developed with one or both lineages of influenza B viruses, but they are limited by the ability of circulating strains to evade the immune system or vaccination. These vaccines are often ineffective because the mutated part of the flu virus (the HA head) evolves. As a result, the seasonal flu vaccine must be reworked and updated frequently. To overcome these limitations, there is an urgent need for a universal influenza vaccine that contains conserved parts of the virus and provides significant broad cross-protection against different strains of the virus.
“In this study, we engineered structurally stabilized HA stem antigens from influenza B virus and produced bilayer protein nanoparticles as a universal vaccine against influenza B,” said Dr. Baojun Wang, senior author of the study and professor emeritus in the Institute of Biomedical Sciences at State University Georgia. “We found that layered protein nanoparticles incorporated into structurally stabilized constant antigens have potential as a universal influenza vaccine with improved immune protective capacity and breadth.”
The nanoparticle vaccine was tested in cell culture and in mice. Cell culture studies have shown that protein nanoparticles are efficiently absorbed to activate dendritic cells, which are important for inducing protective immune responses against pathogens. The vaccine is recognized as safe, biocompatible, biodegradable and highly immunogenic for animals.
“Our next goal is to combine the influenza A nanoparticles from our previous study with the influenza B nanoparticles we produced and tested here to create a multivalent universal nanoparticle influenza vaccine against influenza A and B,” Wang said.
Study co-authors include Yufeng Song (first author), Wandi Zhu, Ye Wang, Lei Deng, Yao Ma, Chunhong Dong, Gilbert X. Gonzalez, Joo Kim, Lai Wei, Sun Mu Kang and Bao Zhong Wang from the Center for Inflammation, Immunity and Infection at the Georgia Institute of Biomedical Sciences. Deng is also affiliated with Hunan University in Changsha, China.
The study is funded by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH).