Phenoloxidase Activity Acts as a Mosquito Innate Immune Response against Infection with Semliki Forest Virus

PLoS Pathogens

Markus H. Beck¹  Mhairi C. Ferguson²  Margo E. Chase-Topping³  Michael R. Strand³  Gerald Barry⁴  Seema Rani⁴  Julio Rodriguez-Andres⁵  Esther Schnettler⁵  Alain Kohl⁵  Rennos Fragkoudis⁵  John K. Fazakerley⁵  Margus Varjak⁵  Andres Merits⁵ 

[1] Centre for Immunity, Infection and Evolution, Ashworth Laboratories, University of Edinburgh, Edinburgh, United Kingdom;Department of Entomology, University of Georgia, Athens, Georgia, United States of America;Institute of Technology, University of Tartu, Tartu, Estonia;MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom;The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, United Kingdom

关键词: Mosquitoes;    Arboviral infections;    Arboviruses;    Viral replication;    Insects;    RNA interference;    Immune response;    Melanin;   

DOI  :  10.1371/journal.ppat.1002977

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Several components of the mosquito immune system including the RNA interference (RNAi), JAK/STAT, Toll and IMD pathways have previously been implicated in controlling arbovirus infections. In contrast, the role of the phenoloxidase (PO) cascade in mosquito antiviral immunity is unknown. Here we show that conditioned medium from the Aedes albopictus-derived U4.4 cell line contains a functional PO cascade, which is activated by the bacterium Escherichia coli and the arbovirus Semliki Forest virus (SFV) (Togaviridae; Alphavirus). Production of recombinant SFV expressing the PO cascade inhibitor Egf1.0 blocked PO activity in U4.4 cell- conditioned medium, which resulted in enhanced spread of SFV. Infection of adult female Aedes aegypti by feeding mosquitoes a bloodmeal containing Egf1.0-expressing SFV increased virus replication and mosquito mortality. Collectively, these results suggest the PO cascade of mosquitoes plays an important role in immune defence against arboviruses.

【 授权许可】

CC BY