A study suggests that a newly developed intranasal influenza vaccine provides robust protection against multiple influenza virus strains.
Designed by researchers at the Institute for Biomedical Sciences at Georgia State University, the novel intranasal influenza vaccine is comprised of nanoparticles that improve immune response and offer strong protection from different strains of the virus. The research indicates that these comprehensive immune responses and cross-protection had a long efficacy, demonstrating defence from influenza for over six months following immunisation.
The research, which was funded by the National Institute of Allergy and Infectious Diseases (NIAID), is published in the journal ACS Applied Materials & Interfaces.
Intranasal influenza vaccine development
Administering vaccines via the nose is a promising approach for infectious respiratory diseases like influenza. Traditional seasonal influenza vaccines elicit narrow immune responses that rapidly decline, meaning they leave those vaccinated with them vulnerable to new strains of the virus. This signifies how vital it is for innovation in influenza vaccine technology to protect against a wide range of influenza viruses. Intranasal vaccination can enhance local mucosal immune responses by eliminating the infection at the portal of virus entry.
Boosting immune response
The HA protein plays a pivotal role in the early stages of the influenza virus and has a head region and a stalk region. Current vaccines create immune responses against the HA head; however, this region is highly changeable and accounts for lowered efficacy against different strains, whereas the HA stalk region is more conservative across different influenza strains.
The team’s new intranasal influenza vaccine is comprised of PEI-HA/CpG nanoparticles. PEI (polyethyleneimine) is a robust and versatile delivery system that transport antigens (hemagglutinin, HA) that trigger an immune response in the body and adjuvants (CpG) that elevate the body’s immune response to an antigen.
Intranasally administered protein antigens are less able to elicit an immune response, meaning adjuvants are required to make the vaccines highly efficient. Adjuvants like CpG can effectively enhance and manipulate immune responses, increasing potency and duration of protection. This was demonstrated in the team’s innovative intranasal influenza vaccine, which achieved a multifaceted immune response, providing strong protection against influenza in rodent models.
Dr Baozhong Wang, the corresponding author of the study and a professor in the Institute for Biomedical Sciences at Georgia State, commented: “The PEI-HA/CpG nanoparticles show good potential as a cross-protective influenza vaccine candidate. The combination of PEI and CpG in the PEI-HA/CpG nanoparticle group contributed to the multifaceted immune responses, leading to vigorous cross-protection. The incorporation of CpG and antigens into the same nanoparticle enhanced cellular immune responses.
“Our results revealed that the nanoparticles significantly enhanced HA immunogenicity, or the ability to provoke an immune response, providing cross-protection against different influenza virus strains. The conserved HA stalk region induced substantial antibodies in the nanoparticle immunisation groups.”
Dr Chunhong Dong, the first author of the study and a postdoctoral fellow in the Institute for Biomedical Sciences, said: “Nanoparticle platforms have shown intriguing characteristics and great potentials in the development of next-generation cross-protective influenza vaccines.
“However, challenges exist to the successful research and development of nanoparticle vaccines. Though no apparent adverse effects were observed in the study, a more comprehensive safety evaluation of the nanoparticle adjuvant system is needed before clinical trials.”