Single Dose of Protein Vaccine with Peptide Nanofibers As Adjuvants Elicits Long-Lasting Antibody Titer.

Self-assembling materials based on peptides have shown great potential as vaccine adjuvants. In our previous work, we have demonstrated that nanofibers based on D-peptide Nap-GDFDFDY are good candidates for vaccine adjuvants. Here we further found that supramolecular hydrogels based on positively charged D-peptide Nap-GDFDFDYDK as vaccine adjuvants could induce stronger immune response. We designed and synthesized two D-peptide derivatives, one with a positive charge (Nap-GDFDFDYDK) and the other with a negative charge (Nap-GDFDFDYDE). Both of them could form the hydrogels constructed by nanofibers. The nanofibers formed by Nap-GDFDFDYDK promoted the more powerful immune response in mice against the antigen chicken egg albumin (OVA) than peptides Nap-GDFDFDY and Nap-GDFDFDYDE. Through cell experiments, we demonstrated that the main reason was that nanofibers formed by Nap-GDFDFDYDK could enhance the uptake of OVA by primary antigen presenting cells. Most importantly, it was intriguing that the nanofibers based on Nap-GDFDFDYDK could evoke long-lasting antibody titers for 28 weeks at a single dose of protein vaccine. Our study demonstrated that supramolecular hydrogels based on positively charged D-peptide were promising vaccine adjuvants and might be very useful for antibody production and vaccine development.