A boosting skin vaccination with a biodegradable microneedle patch and protein constructed from sequences of influenza virus subtypes could improve the effectiveness of conventional influenza vaccines, according to a recent study.

To increase the protection offered by standard influenza vaccines, the Georgia State University researchers made a fusion protein (4M2e-tFliC) with four different sequences of M2e from four different influenza subtypes. M2e is a peptide, a compound of two or more amino acids linked in a chain, found among all influenza strains.The fusion protein also contains flagellin (FliC), a peptide found in nearly all bacteria with flagella (lash-like appendages) that acts as a strong catalyst when administered together with other antigens or foreign substances that induce an immune response in the body.The group condensed the protein into the microneedle patch through collaboration with Georgia Institute of Technology’s Mark R. Prausnitz. The microneedle patch is generated from a biocompatible polymer and the tiny needles arrayed on the patch dissolve and release vaccine into the skin rapidly.

The study found mice receiving a conventional inactivated vaccine, a vaccine consisting of pathogens grown in culture and then killed, followed by a skin-applied dissolving 4M2e-tFliC microneedle patch boost could better maintain the humoral immunity antibody response against influenza virus infection compared to when they received the conventional vaccine alone. The findings offer a new perspective for universal influenza vaccines.Lead researcher Baozhong Wang said that the study demonstrates that M2e-based vaccines greatly improve immune responses and strengthen protective functions against influenza virus infection.

He added that we found that a skin-applied 4M2e-tFliC microneedle patch boosted immunization to seasonal vaccine recipients and may be a rapid approach to increasing the protective efficacy of seasonal vaccines in response to influenza virus challenges. “Thus, the M2e antigen is a promising candidate for the development of universal influenza vaccines."The study is published in the Journal of Controlled Release