Abstract
Nanovaccines co-assemble antigens and adjuvants to elicit robust immune responses but often require complex synthesis and post-modification procedures. Here, a programmable nanovaccine platform based on the M13 bacteriophage is developed for the scalable production of vaccines and single-step modular engineering of adjuvanticity, length, and antigen density. By reprogramming the sequence and size of the noncoding phage genome, the Toll-like receptor 9 activation and the length of the phage are precisely controlled. With a novel molecular engineering approach, the antigen density is tuned from 13.6% to 70.3%. A systematic modulation reveals an optimal adjuvanticity at a constant antigen density for maximum anti-tumor CD8+ T cell response, and vice versa, using the model antigen SIINFEKL. The M13 phage-based nanovaccine induces durable memory immunity lasting over a year. In addition, a 24-fold increase in neoantigen-specific CD8+ T cell frequency is achieved when increasing both the adjuvanticity and antigen density. Furthermore, when combined with anti-PD-1 therapy, the M13 phage-based personalized vaccine eradicates established MC-38 tumors in 75% of treated animals and they develop 100% resistance against tumor invasion when challenged 5 months after treatment. These findings establish M13 phage as a powerful and versatile nanovaccine platform with transformative potential for personalized cancer immunotherapy.