Engineered Resistance to Plasmodium falciparum Development in Transgenic Anopheles stephensi

Alison T Isaacs,Joseph M Vinetz,Anthony A James,Fengwu Li,Xavier Nirmala,Xiaoguang Chen,Nijole Jasinskiene,Osvaldo Marinotti,Nora J Besansky

doi:10.1371/journal.ppat.1002017

Abstract

Transposon-mediated transformation was used to produce Anopheles stephensi that express single-chain antibodies (scFvs) designed to target the human malaria parasite, Plasmodium falciparum. The scFvs, m1C3, m4B7, and m2A10, are derived from mouse monoclonal antibodies that inhibit either ookinete invasion of the midgut or sporozoite invasion of salivary glands. The scFvs that target the parasite surface, m4B7 and m2A10, were fused to an Anopheles gambiae antimicrobial peptide, Cecropin A. Previously-characterized Anopheles cis-acting DNA regulatory elements were included in the transgenes to coordinate scFv production with parasite development. Gene amplification and immunoblot analyses showed promoter-specific increases in transgene expression in blood-fed females. Transgenic mosquito lines expressing each of the scFv genes had significantly lower infection levels than controls when challenged with P. falciparum.

Highlights

Plasmodium falciparum, a causative agent of human malaria, is a vector-borne parasite that is responsible for more than 500 million clinical disease cases each year [1]
Replacement of wild malaria-susceptible mosquito populations with transgenic strains refractory to parasite development could interrupt the cycle of disease transmission and support eradication efforts
We show that An. stephensi engineered to produce P. falciparum-targeting effector molecules are resistant to this important human malaria parasite

Summary

Introduction

Plasmodium falciparum, a causative agent of human malaria, is a vector-borne parasite that is responsible for more than 500 million clinical disease cases each year [1]. A proposed strategy for interrupting transmission is to replace wild, malariasusceptible mosquito populations with transgenic, Plasmodiumresistant mosquitoes [2,3,4]. Key components of this approach are effector molecules that inhibit parasite development when expressed from a transgene. When mosquitoes feed on infected humans, they ingest parasites in the form of gametocytes. These produce gametes that fuse to form diploid zygotes that develop into the motile ookinetes. An effector mechanism based on the mosquito signaling protein Akt is the only one to date shown to inhibit completely P. falciparum development in a transgenic Anopheles mosquito [7]

Methods

Results

Discussion

Conclusion