A new universal flu vaccine protects against influenza B viruses, providing broad defense against different strains and enhanced immune protection, according to a new study by researchers at Georgia State University’s Institute of Biomedical Sciences.
The double-layered protein nanoparticle vaccine, which is constructed with a stabilized part of the influenza virus (the hemagglutinin (HA) stalk), induced broadly reactive immune responses and conferred robust and sustained immune cross-protection against the influenza B virus strains of the two lineages. The results are published in the journal Biomaterials.
Influenza epidemics pose a major threat to public health, and influenza type B has coincided with several severe influenza epidemics. About a quarter of clinical infections are caused by influenza B viruses each year. Influenza B viruses are sometimes the dominant strains circulating during influenza seasons, such as the 2019-2020 U.S. influenza season, when the influenza B caused more than 50% of infections.
Influenza B has two lineages that are genetically distinct and trigger different immune responses. Seasonal influenza vaccines are being developed with one or both influenza B virus lineages, but are limited by the ability of circulating strains to evade the immune system or vaccination. These vaccines are often ineffective because the variable part of the influenza virus (the HA head) evolves. Therefore, seasonal influenza vaccines must be reformulated and updated frequently. To overcome these limitations, a universal influenza vaccine containing conserved parts of the virus and providing substantial broad cross-protection against various viral strains is urgently needed.
“In this study, we generated structure-stabilized HA stem antigens from influenza B and fabricated double-layered protein nanoparticles as universal influenza B vaccine candidates,” said Dr. Baozhong Wang, lead author of the study and professor emeritus at the Institute for Biomedical Sciences at Georgia State University. “We have found that layered protein nanoparticles incorporated into constant structure-stabilized antigens have potential as a universal influenza vaccine with enhanced potency and magnitude of immune protection.”
The nanoparticle vaccine has been tested in cell culture and in mice. Cell culture studies revealed that protein nanoparticles were efficiently taken up to activate dendritic cells, which are essential for inducing protective immune responses against pathogens. The vaccine has been shown to be safe, biocompatible, biodegradable and highly immunogenic in animals.
“Our next goal is to combine the influenza A nanoparticles from our previous study with the influenza B nanoparticles we have fabricated and tested here to create a multivalent universal influenza vaccine against influenza A and B,” said Wang.
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, Sang-Moo Kang, and Bao-Zhong Wang from the Center for Inflammation, Immunity & Infection at the Georgia State 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).