Transgenic Anopheles stephensi coexpressing single-chain antibodies resist Plasmodium falciparum development.
Anopheles stephensi mosquitoes expressing m1C3, m4B7, or m2A10 single-chain antibodies (scFvs) have significantly lower levels of infection compared to controls when challenged with Plasmodium falciparum, a human malaria pathogen. These scFvs are derived from antibodies specific to a parasite chitinase, the 25 kDa protein and the circumsporozoite protein, respectively. Transgenes comprising m2A10 in combination with either m1C3 or m4B7 were inserted into previously-characterized mosquito chromosomal "docking" sites using site-specific recombination. Transgene expression was evaluated at four different genomic locations and a docking site that permitted tissue- and sex-specific expression was researched further. Fitness studies of docking site and dual scFv transgene strains detected only one significant fitness cost: adult docking-site males displayed a late-onset reduction in survival. The m4B7/m2A10 mosquitoes challenged with P. falciparum had few or no sporozoites, the parasite stage infective to humans, in three of four experiments. No sporozoites were detected in m1C3/m2A10 mosquitoes in challenge experiments when both genes were induced at developmentally relevant times. These studies support the conclusion that expression of a single copy of a dual scFv transgene can completely inhibit parasite development without imposing a fitness cost on the mosquito.
Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, CA 92697-4500, USA.
Alison T
AT
Isaacs
Nijole
N
Jasinskiene
Mikhail
M
Tretiakov
Isabelle
I
Thiery
Agnès
A
Zettor
Catherine
C
Bourgouin
Anthony A
AA
James
D000818:Animals; D030801:Animals, Genetically Modified; D000852:Anopheles / Q000235:genetics* / Q000276:immunology* / Q000469:parasitology*; D001665:Binding Sites; D009033:Culicidae; D005260:Female; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D005818:Genetic Engineering / Q000379:methods; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008957:Models, Genetic; D010957:Plasmids / Q000378:metabolism; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D057127:Single-Chain Antibodies / Q000737:chemistry*; D034101:Sporozoites / Q000378:metabolism; D019076:Transgenes
D057127:Single-Chain Antibodies