Symposium Presentation Australian Society for Microbiology Annual Scientific Meeting 2024

A whole organism vaccine approach to target parasites of medical and veterinary importance (103837)

Danielle Stanisic 1
  1. Institute for Glycomics, Griffith University, Southport, Queensland, Australia

Malaria remains a leading cause of morbidity and mortality globally.  The possibility of a malaria vaccine was first realized in the 1940s, yet a highly effective malaria vaccine capable of inducing long-lasting protection remains elusive.  We’ve demonstrated that a chemically attenuated whole parasite blood-stage malaria vaccine, offers strong strain-transcending CD4+ T cell-dependent protection against blood-stage challenge in pre-clinical rodent malaria models.  In malaria-naïve human volunteers, a chemically attenuated whole parasite Plasmodium falciparum blood-stage vaccine was also shown to prevent blood-stage malaria infection from developing in a proportion of vaccinees, following experimental blood-stage parasite challenge.  This is the first time, to our knowledge, that a blood-stage malaria vaccine has completely prevented the development of blood-stage infection in human volunteers.  Although chemically attenuated blood-stage malaria parasites are promising as a vaccine candidate, their application in malaria-endemic areas is logistically and practically challenging due to the requirement for the vaccine to contain a precise dose of intact parasitised red blood cells.  To progress this whole parasite blood-stage vaccine approach we re-formulated the blood-stage parasites with liposomes.  We observed in rodent models that this liposomal vaccine candidate was also highly efficacious and maintained potency following freezing or lyophilisation, ensuring that it is suitable for field deployment.  Following the encouraging results for this vaccine platform in rodent malaria models, we also applied it to the related Apicomplexan Babesia parasite, which causes babesiosis in both humans and animals (e.g. cattle and dogs).  A lyophilised Babesia whole parasite blood-stage liposomal vaccine was shown to induce strong species-transcending protective immunity in rodent models.  This Babesia vaccine approach has both human and veterinary applications.  Both malaria and babesiosis liposomal vaccine candidates are now progressing into clinical trials.