LAUSR

Nanodiamonds (NDs), which are safe carbon nanomaterials, have been used for the transmission of DNA, proteins and drugs. The feasibility of utilizing NDs to deliver NH2-PLGA nanoparticle-encapsulated fig polysaccharides for strongly enhanced immune responses has not been clearly studied. In this study, we aimed to use NDs as carriers to deliver NH2-PLGA nanoparticle-encapsulated fig polysaccharides for strongly enhanced immune responses. ND particles with a diameter of 5 nm were functionalized by surface carboxylation and covalently conjugated with NH2-PLGA nanoparticle-encapsulated fig polysaccharides. NDs-PLGA-FP/OVA could promote antigen uptake and lymphocyte proliferation, increase the expression levels of MHC II, CD80 and CD86, and upregulate the ratio of Th1/Th2 cells in immunized mice. NDs-PLGA-FP/OVA could also upregulate the IL-17 signalling pathway for further immunological enhancement. NDs-PLGA-FP/OVA induced increased TNF-α, IFN-γ, IL-4, and IL-6 cytokine secretion and the levels of OVA-specific antibodies (IgG). These findings demonstrate that NDs-PLGA-FP/OVA have the potential to serve as an effective vaccine delivery and adjuvant system to induce vigorous and long-term immune responses.