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

Area of Science:

• Malariology
• Vaccinology
• Biotechnology

Background:

• Malaria remains a significant global health burden, with existing vaccines offering limited efficacy.
• Current malaria vaccines face challenges including limited reductions in case numbers and cold-chain dependency.

Purpose of the Study:

• To develop and evaluate a novel dual-antigen malaria vaccine, Pfs47-RTS,S-BP, for enhanced immunogenicity and protective efficacy.
• To assess the thermostability of the Pfs47-RTS,S-BP vaccine to address cold-chain limitations in malaria-endemic regions.

Main Methods:

• Engineered Escherichia coli were used to create biopolymer particles (BPs) conjugating the RTS,S antigen and Pfs47 subdomain.
• The immunogenicity and protective efficacy of the dual-antigen Pfs47-RTS,S-BP were compared to single-antigen BPs.
• Thermostability was assessed by evaluating physical properties and antigenicity after storage at 37°C.

Main Results:

• The Pfs47-RTS,S-BP formulation demonstrated synergistic enhancement in immunogenicity and protective efficacy compared to single-antigen BPs.
• The vaccine candidate exhibited promising thermostability, retaining properties after storage at 37°C.
• Pfs47-RTS,S-BP induced durable antibody and T cell responses, including liver-resident memory T cells, with high RTS,S-specific antibody levels and significant protection against challenge and transmission.

Conclusions:

• The Pfs47-RTS,S-BP vaccine represents a promising dual-stage candidate with enhanced immunogenicity and thermostability.
• This novel formulation has the potential to overcome limitations of current malaria vaccines and improve global malaria control.
• Further in vivo assessment of thermostable formulations is warranted to fully evaluate its potential in malaria-endemic regions.