Researchers of the Institute for Biomedical Sciences at Georgia State University have found that a nanoparticles-based intranasal influenza vaccine enhances strong immune response, offering robust protection against different strains of the flu virus, according to Science Daily.

The vaccine, administered through the nose, contributed to multifaceted immune responses, resulting in strong, long-lasting cross protection against flu in mice.

The vaccine contains PEI-HA/CpG nanoparticles. PEI (polyethyleneimine) is a robust and versatile delivery system that can simultaneously carry antigens, like HA (hemagglutinin), inducing an immune response in the body. And adjuvants like (CpG) enhance the body’s immune response to an antigen for optimal immune enhancement.

Intranasal vaccination is one of the ideal approaches for infectious respiratory diseases. It can improve local mucosal immune responses by preventing influenza infection at the portal of virus entry, per Science Daily.

Protein antigens administered intranasally are usually less able to induce an immune response, so adjuvants are needed to increase the efficacy of intranasal vaccines. For instance, CpG has the ability to enhance and manipulate immune responses, improving the potency of protection.

The study’s corresponding author Dr. Baozhong Wang said, “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,” he added. “The conserved HA stalk region induced substantial antibodies in the nanoparticle immunization groups.”

The study’s first author Dr. Chunhong Dong 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,” she added, “a more comprehensive safety evaluation of the nanoparticle adjuvant system is needed before clinical trials.” The study, funded by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH), was published in the journal ACS Applied Materials & Interfaces.