Creation and preclinical evaluation of genetically attenuated malaria parasites arresting growth late in the liver

Blandine Franke-Fayard, Catherin Marin-Mogollon, Fiona J.A. Geurten, Séverine Chevalley-Maurel, Jai Ramesar, Hans Kroeze, Els Baalbergen, Els Wessels, Ludivine Baron, Valérie Soulard, Thomas Martinson, Maya Aleshnick, Antonius T.G. Huijs, Amit K. Subudhi, Yukiko Miyazaki, Ahmad Syibli Othman, Surendra Kumar Kolli, Olivia A.C. Lamers, Magali Roques, Rebecca R. StanwaySean C. Murphy, Lander Foquet, Diana Moita, António M. Mendes, Miguel Prudêncio, Koen J. Dechering, Volker T. Heussler, Arnab Pain, Brandon K. Wilder, Meta Roestenberg, Chris J. Janse

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Whole-sporozoite (WSp) malaria vaccines induce protective immune responses in animal malaria models and in humans. A recent clinical trial with a WSp vaccine comprising genetically attenuated parasites (GAP) which arrest growth early in the liver (PfSPZ-GA1), showed that GAPs can be safely administered to humans and immunogenicity is comparable to radiation-attenuated PfSPZ Vaccine. GAPs that arrest late in the liver stage (LA-GAP) have potential for increased potency as shown in rodent malaria models. Here we describe the generation of four putative P. falciparum LA-GAPs, generated by CRISPR/Cas9-mediated gene deletion. One out of four gene-deletion mutants produced sporozoites in sufficient numbers for further preclinical evaluation. This mutant, PfΔmei2, lacking the mei2-like RNA gene, showed late liver growth arrest in human liver-chimeric mice with human erythrocytes, absence of unwanted genetic alterations and sensitivity to antimalarial drugs. These features of PfΔmei2 make it a promising vaccine candidate, supporting further clinical evaluation. PfΔmei2 (GA2) has passed regulatory approval for safety and efficacy testing in humans based on the findings reported in this study.

Original languageEnglish (US)
Article number139
Journalnpj Vaccines
Issue number1
StatePublished - Dec 2022

ASJC Scopus subject areas

  • Immunology
  • Pharmacology
  • Infectious Diseases
  • Pharmacology (medical)


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