PfRH5 Antibody Combinations to Reduce Merozoite Red Blood Cell Invasion
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Solution Overview
Problem
Current malarial vaccines, such as RTS,S/AS01, have limited efficacy against the blood-stage Plasmodium parasite, and antibodies targeting PfAMA1 are strain-specific and require high concentrations, while PfRH5 antigens show promise but need improved antibodies for broader effectiveness and synergy.
Innovation Solution
Development of non-neutralizing antibodies that bind to a specific region of PfRH5 and synergize with neutralizing antibodies against PfRH5 and other merozoite antigens, such as PfAMA1, to enhance immune response and inhibit parasite invasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PfAMA1 antigen is used to induce antibodies, then antibodies are effective against blood-stage malaria parasites, but antibodies are only effective at extremely high concentrations and are strain-specific
Solution Approach 1:
The patent changes the target antigen from PfAMA1 to PfRH5, which induces antibodies that are effective at lower concentrations. This parameter change in antigen selection resolves the contradiction by maintaining effectiveness while reducing the required antibody concentration.
Solution Approach 2:
The patent develops PfRH5 antibodies that are effective against genetically diverse strains of Plasmodium parasite, providing universal protection. This multi-strain effectiveness resolves the strain-specific limitation of PfAMA1 antibodies while maintaining reliability across different parasite variants.
2Reliability
If PfAMA1 antigen is used, then antibodies are induced against blood-stage malaria, but chemical adjuvants are required to induce sufficient antibody responses
Solution Approach 1:
The patent changes the antigen from PfAMA1 to PfRH5, which naturally induces stronger and more sustained antibody responses without requiring potentially reactogenic chemical adjuvants. This parameter change resolves the contradiction by achieving sufficient antibody response while eliminating harmful adjuvant effects.
3Reliability
If RTS,S/AS01 vaccine is used, then protection against liver-stage Plasmodium is achieved, but efficacy against blood-stage parasite is limited to 30-50%
Solution Approach 1:
The patent segments the malaria parasite lifecycle into distinct stages (liver-stage and blood-stage) and develops targeted vaccines for each stage. The PfRH5 vaccine specifically targets the blood-stage invasion process, complementing the liver-stage protection of RTS,S/AS01 and achieving comprehensive multi-stage coverage.
Solution Approach 2:
The patent creates a vaccine strategy that provides universal protection across multiple parasite stages and strains. By targeting PfRH5, which is essential for blood-stage invasion across diverse Plasmodium strains, the vaccine achieves broad-spectrum effectiveness while maintaining stage-specific precision.
4Adaptability or versatility
If other protein families involved in blood-stage invasion are targeted, then vaccine candidates are identified, but they are ineffective or less effective than PfAMA1 in GIA assay
Solution Approach 1:
The patent changes the selection criterion from GIA assay performance to functional importance in parasite invasion. By selecting PfRH5 based on its critical role in merozoite-RBC binding rather than preliminary GIA results, the patent identifies an antigen that proves highly effective, reversing the effectiveness ranking of candidate antigens.
Data Source
AI summary
There are provided antibodies and combination thereof, and other binding proteins against malarial antigens, as well as said antigens and vectors encoding the antibodies and antigens. The invention also provides the use of such compounds and combinations thereof in the prevention or treatment of malaria. In particular, synergistic combinations of non-neutralising antibodies directed towards an epitope on Reticulocyte-binding protein Homologue 5 (PfRH5) and neutralising antibodies directed towards Plasmodium merozoite antigens are provided.