Replication of Bunyamwera virus in mosquito cells

Bunyaviruses;Mosquitoes--Cytology;Virology--Cultures and culture media

Szemiel, Agnieszka M. ; Elliott, Richard Michael ; Elliott, Richard Michael

University:University of St Andrews

Department:Research Centres and Institutes

关键词: Bunyaviruses;    Mosquitoes--Cytology;    Virology--Cultures and culture media;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/2570/AgnieszkaSzemielPhDThesis.pdf?sequence=6&isAllowed=y

来源: DR-NTU

【 摘 要 】

The Bunyaviridae family is one of the largest among RNA viruses, comprising morethan 350 serologically distinct viruses. The family is classified into five genera,Orthobunyavirus, Hantavirus, Nairovirus, Phlebovirus, and Tospovirus.Orthobunyaviruses, nairoviruses and phleboviruses are maintained in nature by apropagative cycle involving blood-feeding arthropods and susceptible vertebrate hosts.Like most arthropod-borne viruses, bunyavirus replication causes little damage to thevector, whereas infection of the mammalian host may lead to death. This situation ismimicked in the laboratory: in cultured mosquito cells no cytopathology is observedand a persistent infection is established, whereas in cultured mammalian cellsorthobunyavirus infection is lytic and leads to cell death.Bunyaviruses encode four common structural proteins: an RNA-dependent RNApolymerase, two glycoproteins (Gc and Gn), and a nucleoprotein N. Some viruses alsocode for nonstructural proteins called NSm and NSs. The NSs protein of the prototypebunyavirus, Bunyamwera virus, seems to be one of the factors responsible for thedifferent outcomes of infection in mammalian and mosquito cell lines. However, onlylimited information is available on the growth of bunyaviruses in cultured mosquito celllines other than Aedes albopictus C6/36 cells. Here, I compared the replication ofBunyamwera virus in two additional Aedes albopictus cell clones, C7-10 and U4.4, andtwo Aedes aegypti cell clones, Ae and A20, and investigated the impact of virusreplication on cell function. In addition, whereas the vertebrate innate immuneresponse to arbovirus infection is well studied, relatively little is known aboutmosquitoes’ reaction to these infections. I investigated the immune responses of thedifferent mosquito cells to Bunyamwera virus infection, in particular antimicrobialsignaling pathways (Toll and IMD) and RNA interference (RNAi). The data obtained inU4.4 cells suggest that NSs plays an important role in the infection of mosquitoes.Moreover infection of U4.4 cells more closely resembles infection in Ae and A20 cellsand live Aedes aegypti mosquitoes. My data showed that the investigated cell lineshave various properties, and therefore they can be used to study different aspects ofmosquito-virus interactions.