Abstract
Background: Short peptide hydrogel was reported as a possible adjuvant for vaccines. In order to evaluate whether the Tetra-Peptide Hydrogel can be a promising adjuvant for an H7N9 vaccine against the highly pathogenic H7N9 virus, we conducted this study. Methods: Tetra-Peptide Hydrogels (D and L conformations) were prepared by a self-assembly system using a Naproxen acid modified tetra peptide of GFFY (Npx-GFFY). Mice received two immunizations with the D-Tetra-Peptide Hydrogel adjuvant vaccine, the L-Tetra-Peptide Hydrogel adjuvant vaccine, or the split vaccine. Fourteen days following the second dose, the mice were challenged with the highly pathogenic A/Guangdong/GZ8H002/2017(H7N9) virus. The mice were observed for signs of illness, weight loss, pathological alterations of the lung tissues and immune responses in the following 2 weeks. Results: The D/L-Tetra-Peptide Hydrogels resembled long bars with hinges on each other, with a diameter of ~10 nm. The H7N9 vaccine was observed to adhere to the hydrogel. All the unvaccinated mice were dead by 8 days post infection with H7N9. The mice immunized by the split H7N9 vaccine were protected against infection with H7N9. Mice immunized by D/L-Tetra-Peptide Hydrogel adjuvant vaccines experienced shorter symptomatic periods and their micro-neutralization titers were higher than in the split H7N9 vaccine at 2 weeks post infection. The hemagglutinating inhibition (HI) titer in the L-Tetra-Peptide Hydrogel adjuvant vaccine group was higher than that in the split H7N9 vaccine 1 week and 2 weeks post infection. The HI titer in the D-Tetra-Peptide Hydrogel adjuvant vaccine group was higher than that in the split H7N9 vaccine at 2 weeks post infection. Conclusion: The D/L Tetra-Peptide Hydrogels increased the protection of the H7N9 vaccine and could be promising adjuvants for H7N9 vaccines against highly pathogenic H7N9 virus.
Highlights
Throughout its history, mankind has fought against infectious diseases
To enhance the activity of the H7N9 vaccine against highly pathogenic H7N9 virus, we developed Tetra-Peptide Hydrogel (D and L conformations) adjuvants
The present study was conducted to determine if the TetraPeptide Hydrogel adjuvants could enhance the immunity of the H7N9 vaccine
Summary
Throughout its history, mankind has fought against infectious diseases. Examples of infectious diseases experienced by humans include cholera; plague; smallpox; yellow fever; schistosomiasis; malaria; influenza; polio; whooping cough; diphtheria; measles; mumps; rubella; B encephalitis; epidemic meningitis; AIDS; syphilis; viral hepatitis; tuberculosis; Ebola virus disease; atypical pneumonia; Middle East respiratory syndrome; Zika virus disease; hand, foot and mouth disease; dengue fever; avian influenza; novel coronavirus disease and so on [1,2,3,4,5,6,7,8,9,10]. Vaccines play an important role in controlling infectious diseases. The adjuvant itself can significantly activate the body’s immune system, improve the level of multiple cytokines (interleukin (IL), IL6, interferon (IFN)-γ, tumor necrosis factor alpha (TNFα)), and aid the development of vaccines against tumors, viruses, and other infectious agents [23]. The split H7N9 vaccine could protect BALB/c mice against highly pathogenic H7N9 virus infection; the protective effect decreased because of mutation of H7N9 [31]. To enhance the activity of the H7N9 vaccine against highly pathogenic H7N9 virus, we developed Tetra-Peptide Hydrogel (D and L conformations) adjuvants. The present study was conducted to determine if the TetraPeptide Hydrogel (formed by Npx-GFFY) adjuvants could enhance the immunity of the H7N9 vaccine
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