Alternative antigen retention by a gp96-fusion approach induces long-lasting and broad immunity in mice.

Efficient antigen delivery to B cells and dendritic cells (DC) is critical for enhancing vaccine immunogenicity. Here, we develop a dimeric vaccine strategy by fusing antigens to the N-terminal of heat shock protein GP96. This platform generates compact, nanoscale particles that fully exposed antigenic sites. We validate the vaccine strategy using the SARS-CoV-2 receptor-binding domain (RBD) antigen in a viral challenge model with hACE2 mice and the human papillomavirus (HPV) E7 protein in a HeLa xenograft model with nude mice. The GP96 moiety directly bound its receptor, LRP1, thereby enhancing antigen accumulation on follicular DCs and prolonging lymph node retention, ultimately amplifying germinal center B cell responses. Furthermore, GP96-LRP1 interaction on DCs promotes antigen endocytosis, underpinning epitope presentation and robust cross-conserved T cell activation. Consequently, this design induces potent, durable humoral immunity, cross-conserved T cell responses, and pulmonary mucosal immunity, underscoring its promise as a versatile and effective vaccination strategy.