Lentinan-Functionalized Graphene Oxide Is an Effective Antigen Delivery System That Modulates Innate Immunity and Improves Adaptive Immunity

Graphene oxide (GO) and lentinan have received great attention because of their utility in biomedical applications. Graphene oxide is utilized in drug- and vaccine-delivery systems due to its biocompatibility, large surface area, and outstanding adsorption capability, while lentinan has immunity-enhancing effects. In this study, we synthesized and characterized GO grafted with lentinan (LNT) as an adjuvant and investigated how to impact the immune responses. Lentinan-modified GO (GO-LNT) facilitated antigen uptake in macrophages and improved the efficiency of antigen application in vitro. Furthermore, in vivo, compared with GO/OVA, GO-LNT/OVA decreased the release rate of ovalbumin (OVA) to sustain long-term immune responses and boost the levels of IgG and IgG subtypes. Hence, we can infer that the effects of GO-LNT were a result of the increased amounts of antigen uptake by cells. Overall, our studies demonstrated that GO-LNT could suffice for a safe and effective vaccine-delivery system as well as an excellent adjuvant that both elicits a long-term immune memory response and potentiates cellular and humoral immunity.