A vaccine that is administered intranasally is very convenient to combat infectious diseases of the respiratory system, such as the flu. In the case of this infection, in addition, the available flu vaccines usually generate a limited and rapidly declining immune response, leaving the most vulnerable people unprotected against new strains of the flu virus.
Intranasal vaccination is precisely capable of improving the immune responses of the mucous membranes of the nose because it prevents infection from the very door through which the virus sneaks in, and now a group of scientists from the Institute of Biomedical Sciences at Georgia State University (United States) has developed a flu vaccine made with nanoparticles that improve the immune response, providing effective protection against different strains of the influenza virus, and which is also administered through the nostrils.
This intranasal vaccine induced multifaceted immune responses, leading to potent cross-protection against influenza in mice tested. The drug contains PEI-HA/CpG nanoparticles. Polyethyleneimine (PEI) is a robust and versatile delivery system that can simultaneously deliver antigens (hemagglutinin, HA) that induce an immune response in the body and adjuvants (CpG) that enhance the body’s immune response to an antigen for immune boosting optimum.
“Our results revealed that the nanoparticles significantly enhanced the ability to elicit an immune response, providing cross-protection against different strains of the influenza virus.”
These comprehensive immune responses and cross-protection were long-lasting and proved capable of providing defense against influenza virus for more than six months after immunization. The results of the research have been published in the journal ACS Applied Materials & Interfaces.
Nanoparticles that improve the immune response and its duration
The HA protein plays a key role in the early stages of influenza virus infection. Influenza HA has a head zone and a stem zone, and current influenza vaccines elicit immune responses against the HA head, but this head region is highly variable, explaining decreased efficacy against different strains. The HA stem region, on the other hand, is more conservative in different strains of influenza viruses.
Protein antigens that are administered intranasally tend to have a lower ability to induce an immune response, therefore adjuvants are needed to create intranasal vaccines with high efficacy. Adjuvants, such as CpG, can enhance and direct immune responses, improving both the intensity and extent of protection.
“Although no apparent adverse effects were observed in the study, a more comprehensive safety evaluation of the nanoparticle adjuvant system is needed prior to clinical trials.”
“PEI-HA/CpG nanoparticles show good potential as cross-protective influenza vaccine candidates,” said Dr. Baozhong Wang, corresponding author of the study and professor at the Georgia State Institute of Biomedical Sciences. “The combination of PEI and CpG in the PEI-HA/CpG nanoparticle pool contributed to multifaceted immune responses, leading to vigorous cross-protection. The incorporation of CpG and antigens in the same nanoparticle enhanced cellular immune responses”.
“Our results revealed that the nanoparticles significantly enhanced the immunogenicity of HA, or the ability to elicit an immune response, providing cross-protection against different influenza virus strains. The conserved HA stem region induced substantial antibodies in the nanoparticle immunization groups.”
“Nanoparticle platforms have shown intriguing features and great potential in the development of next-generation cross-protective influenza vaccines,” said Dr. Chunhong Dong, first author of the study and postdoctoral fellow at the Institute of Biomedical Sciences. . “However, there are challenges to the successful research and development of nanoparticle vaccines. Although no apparent adverse effects were observed in the study, a more comprehensive safety evaluation of the nanoparticle adjuvant system is needed prior to clinical trials.”
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