Robust Bioconjugated Antigens Induce Immune Responses Preventing Malaria Infection and its Transmission

Malaria remains a major global health challenge, with current vaccines providing only limited reductions in case numbers. This study introduces an innovative approach that utilizes engineered Escherichia coli to bioconjugate and assemble the pre-erythrocytic circumsporozoite protein-derived RTS,S antigen and the sexual-stage Pfs47 subdomain into biopolymer particles (BPs), generating the dual-antigen Pfs47-RTS,S-BP vaccine. Compared to single-antigen BPs, the fused Pfs47-RTS,S-BP formulation shows synergistic enhancement in immunogenicity and protective efficacy. Pfs47‑RTS,S‑BP retains its physical properties and antigenicity after storage at 37°C. Although functional in vivo assessment of these thermostable formulations has not yet been performed, the findings indicate promising thermostability that could help overcome cold‑chain limitations in malaria‑endemic regions. Pfs47-RTS,S-BP induces durable antibody and T cell responses alongside crucial liver-resident memory T cells for frontline defence. Vaccine-induced antibodies efficiently neutralize sporozoites and inhibit parasite transmission. Pfs47-RTS,S-BP generates RTS,S-specific antibody levels 5.3-fold higher than the protective thresholds of the current RTS,S/AS01 vaccine. The Pfs47-RTS,S-BP formulation also achieves 80.4% protection against mosquito bite challenge and 68.15% transmission-reducing activity, demonstrating strong potential as a robust, dual-stage malaria vaccine candidate. Overall, this work underscores the potential of Pfs47‑RTS, S‑BP to overcome key limitations of current vaccines and to substantially advance global malaria control efforts.