Innovative Mucosal Adjuvant Enhances Efficacy of Influenza Vaccines

ATLANTA — A recent study conducted by researchers at Georgia State University's Institute for Biomedical Sciences has revealed that a novel mucosal adjuvant significantly boosts the effectiveness of influenza hemagglutinin subunit vaccines. The research, published in the journal *ACS Nano* on July 2, 2025, highlights the potential of immune cell-derived extracellular vesicles to enhance immune responses against various influenza virus strains.

The study shows that combining the hemagglutinin vaccine with a mucosal adjuvant derived from mature bone marrow-derived dendritic cells results in improved cross-protection against diverse influenza challenges. According to Dr. Bao-Zhong Wang, a Distinguished University Professor at Georgia State University and senior author of the study, “Immune cell-derived extracellular vesicles, which play crucial roles in intercellular communication and modulating biological responses, are potent mucosal adjuvants for influenza hemagglutinin vaccines.”

The influenza hemagglutinin subunit vaccine primarily contains the hemagglutinin protein, vital for the virus's ability to infect host cells. Existing seasonal vaccines have shown limited effectiveness against evolving strains, underscoring the urgent need for next-generation vaccines. The introduction of mucosal immunization strategies is especially promising as they can prevent infection at the respiratory tract, a primary entry point for the virus.

The research team discovered that the extracellular vesicles derived from mature dendritic cells effectively activated antigen-presenting cells, macrophages, and B cells. This activation was demonstrated both in vitro and in vivo, leading to enhanced recruitment of airway immune cells and robust germinal center formation in animal models. These findings suggest that mucosal vaccines could offer a more targeted approach to vaccination against respiratory pathogens.

Chunhong Dong, the first author of the study and a postdoctoral fellow at the Institute for Biomedical Sciences, emphasized the significance of these findings: “Given their biocompatibility and solid adjuvanticity, mature bone marrow-derived dendritic cells represent a promising adjuvant candidate for mucosal vaccine development.”

The implications of this research extend beyond influenza, as the potential for using such adjuvants in other mucosal vaccines could revolutionize vaccine strategies for various infectious diseases. The study was funded by the National Institutes of Health (NIH) and highlights a critical advancement in the field of vaccine development, particularly for diseases that pose significant public health challenges.

As the world continues to grapple with evolving viral threats, innovative solutions like these could play a crucial role in enhancing the effectiveness of vaccines and ultimately improving global health outcomes. The researchers advocate for further studies to explore the full potential of extracellular vesicles in immunotherapy and vaccine development, paving the way for more effective vaccines in the future.