Intranasal (i.n.) immunization is a promising vaccination route for infectious respiratory diseases such as influenza. Recombinant protein vaccines can overcome the safety concerns and long production phase of virus-based influenza vaccines. However, soluble protein vaccines are poorly immunogenic if administered by an i.n. route. Here, we report that polyethyleneimine-functionalized graphene oxide nanoparticles (GP nanoparticles) showed high antigen-loading capacities and superior immunoenhancing properties. Via a facile electrostatic adsorption approach, influenza hemagglutinin (HA) was incorporated into GP nanoparticles and maintained structural integrity and antigenicity. The resulting GP nanoparticles enhanced antigen internalization and promoted inflammatory cytokine production and JAWS II dendritic cell maturation. Compared with soluble HA, GP nanoparticle formulations induced significantly enhanced and cross-reactive immune responses at both systemic sites and mucosal surfaces in mice after i.n. immunization. In the absence of any additional adjuvant, the GP nanoparticle significantly boosted antigen-specific humoral and cellular immune responses, comparable to the acknowledged potent mucosal immunomodulator CpG. The robust immune responses conferred immune protection against challenges by homologous and heterologous viruses. Additionally, the solid self-adjuvant effect of GP nanoparticles may mask the role of CpG when coincorporated. In the absence of currently approved mucosal adjuvants, GP nanoparticles can be developed into potent i.n. influenza vaccines, providing broad protection. With versatility and flexibility, the GP nanoplatform can be easily adapted for constructing mucosal vaccines for different respiratory pathogens.

鼻内免疫是流感等传染性呼吸道疾病的一种有前景的疫苗接种途径。重组蛋白疫苗可以克服基于病毒的流感疫苗的安全性问题和较长的生产周期。然而，如果通过途径施用，可溶性蛋白疫苗的免疫原性很差。在这里，我们报告聚乙烯亚胺功能化氧化石墨烯纳米颗粒（GP纳米颗粒）表现出高抗原负载能力和优异的免疫增强特性。通过简便的静电吸附方法，流感血凝素 (HA) 被纳入 GP 纳米颗粒中，并保持结构完整性和抗原性。由此产生的 GP 纳米粒子增强了抗原内化并促进炎症细胞因子的产生和 JAWS II 树突状细胞的成熟。与可溶性HA相比，GP纳米颗粒制剂在免疫后在小鼠全身部位和粘膜表面均诱导显着增强的交叉反应性免疫反应。在没有任何额外佐剂的情况下，GP 纳米颗粒显着增强了抗原特异性体液和细胞免疫反应，与公认的有效粘膜免疫调节剂 CpG 相当。强大的免疫反应提供了针对同源和异源病毒挑战的免疫保护。此外，GP 纳米粒子的固体自佐效应可能会掩盖 CpG 的作用。在目前尚无批准的粘膜佐剂的情况下，GP纳米颗粒可以开发成有效的流感疫苗，提供广泛的保护。 GP纳米平台具有多功能性和灵活性，可以轻松适应构建针对不同呼吸道病原体的粘膜疫苗。