Plasmodium falciparum reticulocyte-binding protein homolog 5 (RH5) is a leading blood-stage malaria vaccine antigen target, currently in a phase 2b clinical trial as a full-length soluble protein/adjuvant vaccine candidate called RH5.1/Matrix-M. We identify that disordered regions of the full-length RH5 molecule induce non-growth inhibitory antibodies in human vaccinees and that a re-engineered and stabilized immunogen (including just the alpha-helical core of RH5) induces a qualitatively superior growth inhibitory antibody response in rats vaccinated with this protein formulated in Matrix-M adjuvant. In parallel, bioconjugation of this immunogen, termed "RH5.2," to hepatitis B surface antigen virus-like particles (VLPs) using the "plug-and-display" SpyTag-SpyCatcher platform technology also enables superior quantitative antibody immunogenicity over soluble protein/adjuvant in vaccinated mice and rats. These studies identify a blood-stage malaria vaccine candidate that may improve upon the current leading soluble protein vaccine candidate RH5.1/Matrix-M. The RH5.2-VLP/Matrix-M vaccine candidate is now under evaluation in phase 1a/b clinical trials.
Journal article
Cell reports. Medicine
07/2024
5
Department of Biochemistry, University of Oxford, Dorothy Crowfoot Hodgkin Building, OX1 3QU Oxford, UK; Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building, University of Oxford, OX1 3QU Oxford, UK; The Jenner Institute, University of Oxford, Old Road Campus Research Building, OX3 7DQ Oxford, UK.
Animals, Mice, Inbred BALB C, Humans, Mice, Rats, Plasmodium falciparum, Malaria, Falciparum, Carrier Proteins, Protozoan Proteins, Malaria Vaccines, Antibodies, Protozoan, Antigens, Protozoan, Female, Vaccines, Virus-Like Particle