Development of a novel carbon dot adjuvant for infectious disease vaccine 3348

Abstract Description Adjuvants are crucial for vaccines, enhancing humoral and cellular immunity, thereby reducing the required antigen dose. Traditional adjuvants, such as aluminum salts, primarily induce humoral responses but fail to elicit cellular immunity critical for combating cancers and viral infections. This limitation has driven interest in novel adjuvants, such as γ-PGA, a biodegradable polymer from Bacillus subtilis that activates TLR4-mediated innate immunity and promotes Th1 responses, enhancing vaccine efficacy. Carbon dots (CDs), nanoscale carbon-based materials with excellent biocompatibility and tunable properties, have gained attention for biomedical applications. Functionalized CDs boost dendritic cell activation while delivering antigens efficiently, eliciting strong humoral and cellular immune responses with minimal toxicity. Here, we synthesized PGA-CD, a novel adjuvant by conjugating γ-PGA onto a carbon dot core. PGA-CD exhibited no cytotoxicity up to 1 mg/mL and significantly enhanced BMDC activation, inducing higher cytokine levels than γ-PGA. The PGA-CD formed around100 nm antigen-loaded nanoparticles efficiently taken up by cells, eliciting potent humoral and cellular responses. Immunization with PGA-CD/HA induced robust immune responses and provided full protection against influenza infections (pdmH1N1 and PR8). In conclusion, we suggest that PGA-CD is a promising vaccine adjuvant, enhancing immunogenicity and protection against infectious diseases. Funding Sources Supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(RS-2024-00448248) and funded by the Korea government (2023R1A2C2003679) Topic Categories Vaccines and Immunotherapy (VAC)