The protective effects of a D-tetra-peptide hydrogel adjuvant vaccine against H7N9 influenza virus in mice

Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans, with mortality reaching approximately 40%-50%. To prevent possible pandemics, the development of highly effective vaccines against influenza virus H7N9 is highly desired. In the present study, by taking advantage of the D-tetra-peptide adjuvant (GDFDFDY), we reported a simple method to prepare H7N9 vaccines. Naproxen (Npx), with good anti inflammatory and broad anti-viral effects, was employed as an N-terminal capping group to construct a hydrogel precursor, Npx-G DF DF DY. The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013 (H7N9) antigen by vortexing. Compared with the traditional Al(OH)(3) adjuvant vaccine and the split vaccine, our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection. A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects. Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.(c) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Repeated waves of H7N9 influenza virus have caused severe influenza in humans since 2013, with a high mortality rate. To prevent possible pandemics, the development of highly effective vaccines against H7N9 is crucial. In this study, a simple method using a peptide hydrogel adjuvant was reported to prepare the H7N9 vaccine, which showed better preventive effects against H7N9 infection compared to traditional adjuvant vaccines. The study also revealed higher antibody responses and variations in cytokine expression as potential mechanisms for the increased protective effects of the hydrogel adjuvant vaccine.