Site‐Specific Modification of Virus‐Like Particles for Exogenous Tumor Antigen Display and Minimizing Preexisting Immunity

Abstract The widespread preexisting immunity against virus‐like particles (VLPs) seriously limits the applications of VLPs as vaccine vectors. Enabling technology for exogenous antigen display should not only ensure the assembly ability of VLPs and site‐specific modification, but also consider the effect of preexisting immunity on the behavior of VLPs in vivo. Here, combining genetic code expansion technique and synthetic biology strategy, a site‐specific modification method for hepatitis B core (HBc) VLPs via incorporating azido‐phenylalanine into the desired positions is described. Through modification position screening, it is found that HBc VLPs incorporated with azido‐phenylalanine at the main immune region can effectively assemble and rapidly conjugate with the dibenzocycolctyne‐modified tumor‐associated antigens, mucin‐1 (MUC1). The site‐specific modification of HBc VLPs not only improves the immunogenicity of MUC1 antigens but also shields the immunogenicity of HBc VLPs themselves, thereby activating a strong and persistent anti‐MUC1 immune response even in the presence of preexisting anti‐HBc immunity, which results in the efficient tumor elimination in a lung metastatic mouse model. Together, these results demonstrate the site‐specific modification strategy enabled HBc VLPs behave as a potent antitumor vaccine and this strategy to manipulate immunogenicity of VLPs may be suitable for other VLP‐based vaccine vectors.