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Sterile protection and transmission blockade by a multistage anti-malarial vaccine in the pre-clinical study.

Published version
Peer-reviewed

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Authors

Iyori, Mitsuhiro 
Blagborough, Andrew M 
Mizuno, Tetsushi 
Abe, Yu-Ichi 
Nagaoka, Mio 

Abstract

The Malaria Vaccine Technology Roadmap 2013 (World Health Organization) aims to develop safe and effective vaccines by 2030 that will offer at least 75% protective efficacy against clinical malaria and reduce parasite transmission. Here, we demonstrate a highly effective multistage vaccine against both the pre-erythrocytic and sexual stages of Plasmodium falciparum that protects and reduces transmission in a murine model. The vaccine is based on a viral-vectored vaccine platform, comprising a highly-attenuated vaccinia virus strain, LC16m8Δ (m8Δ), a genetically stable variant of a licensed and highly effective Japanese smallpox vaccine LC16m8, and an adeno-associated virus (AAV), a viral vector for human gene therapy. The genes encoding P. falciparum circumsporozoite protein (PfCSP) and the ookinete protein P25 (Pfs25) are expressed as a Pfs25-PfCSP fusion protein, and the heterologous m8Δ-prime/AAV-boost immunization regimen in mice provided both 100% protection against PfCSP-transgenic P. berghei sporozoites and up to 100% transmission blocking efficacy, as determined by a direct membrane feeding assay using parasites from P. falciparum-positive, naturally-infected donors from endemic settings. Remarkably, the persistence of vaccine-induced immune responses were over 7 months and additionally provided complete protection against repeated parasite challenge in a murine model. We propose that application of the m8Δ/AAV malaria multistage vaccine platform has the potential to contribute to the landmark goals of the malaria vaccine technology roadmap, to achieve life-long sterile protection and high-level transmission blocking efficacy.

Description

Peer reviewed: True

Keywords

LC16m8Δ, PfCSP, Pfs25, adeno-associated virus (AAV), malaria, plasmodium falciparum, vaccine, Animals, Antibodies, Protozoan, Antimalarials, Dependovirus, Disease Models, Animal, Humans, Malaria Vaccines, Malaria, Falciparum, Mice, Protozoan Proteins

Journal Title

Front Immunol

Conference Name

Journal ISSN

1664-3224
1664-3224

Volume Title

Publisher

Frontiers Media SA
Sponsorship
Medical Research Council (MR/N00227X/1)