ABSTRACT
Antiviral vaccine is essential for preventing and controlling virus spreading, along with declining morbidity and mortality. A major challenge in effective vaccination lies in the ability to enhance both the humoral and cellular immune responses by adjuvants. Herein, self-assembled nanoparticles based on graphene oxide quantum dots with components of carnosine, resiquimod and Zn2+ ions, namely ZnGC-R, are designed as a new adjuvant for influenza vaccine. With its high capability for antigen-loading, ZnGC-R enhances antigen utilization, improves DC recruitment, and activates antigen-presenting cells. Single cell analysis of lymphocytes after intramuscular vaccination revealed that ZnGC-R generated multifaceted immune responses. ZnGC-R stimulated robust CD4+CCR7loPD-1hi Tfh and durable CD8+CD44hiCD62L- TEM immune responses, and simultaneously promoted the proliferation of CD26+ germinal center B cells. Besides, ZnGC-R elicited 2.53-fold higher hemagglutination-inhibiting antibody than commercial-licensed aluminum salt adjuvant. ZnGC-R based vaccine induced 342% stronger IgG antibody responses compared with vaccines with inactivated virus alone, leading to 100% in vivo protection efficacy against the H1N1 influenza virus challenge.
