Research article

Continuous exposure to Plasmodium results in decreased susceptibility and transcriptomic divergence of the Anopheles gambiae immune system

Ruth Aguilar^†, Suchismita Das^†, Yuemei Dong^† and George Dimopoulos^*

• * Corresponding author: George Dimopoulos gdimopou@jhsph.edu

• † Equal contributors

Author Affiliations

W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, 615N. Wolfe Street, Baltimore, MD 21205-2179, USA

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BMC Genomics 2007, 8:451 doi:10.1186/1471-2164-8-451

Published: 5 December 2007

Abstract

Background

Plasmodium infection has been shown to compromise the fitness of the mosquito vector, reducing its fecundity and longevity. However, from an evolutionary perspective, the impact of Plasmodium infection as a selective pressure on the mosquito is largely unknown.

Results

In the present study we have addressed the effect of a continuous Plasmodium berghei infection on the resistance to infection and global gene expression in Anopheles gambiae.

Exposure of A. gambiae to P. berghei-infected blood and infection for 16 generations resulted in a decreased susceptibility to infection, altered constitutive expression levels for approximately 2.4% of the mosquito's total transcriptome and a lower basal level of immune genes expression, including several anti-Plasmodium factors. The infection-responsiveness for several defense genes was elevated in the P. berghei exposed mosquito colonies.

Conclusion

Our study establishes the existence of a selective pressure exerted by the parasite P. berghei on the malaria vector A. gambiae that results in a decreased permissiveness to infection and changes in the mosquito transcriptome regulation that suggest a decreased constitutive immune gene activity but a more potent immune response upon Plasmodium challenge.