Year of Publication

2010

Paper Type

Master's Thesis

College

College of Arts and Sciences

Degree Name

Master of Science in Biology (MS)

Department

Biology

First Advisor

Dr. J. Ochrietor

Second Advisor

Dr. M. Lentz

Third Advisor

Dr. C. Hackney

Abstract

The prototype Alphavirus, Sindbis virus (SIN), relies on cyclic transmission between the mosquito and vertebrate hosts in order to be maintained in nature. This broad host range suggests that alphaviruses use a universally expressed molecule for attachment. Heparan sulfate proteoglycan (HSPG), a ubiquitous SIN receptor present on the cell surface of most eukaryotic cells, has been reported in the salivary glands and midguts of mosquitoes. These organs are essential for virus transmission from this hematophageous invertebrate. Variable host cell response in the mosquito following intrathoracic inoculation with SIN has been documented. In this study, per os infection of Aedine species with variants of SIN was used to determine organ specific responses to virus as well as the temporal kinetics of SIN dissemination via leg assay. Analysis indicated AR339 virus dissemination in samples at day 14 days post infection (p.i.). TR339 was identified at day 12 in legs of virus fed individuals. AR339, the HSPG adapted variant resulted in SIN-associated pathology in salivary glands of Aedes albopictus. This pathology was limited to lateral lobes, while the median lobe remained unaffected. Infection with TR339, a HSPG-independent variant, did not result in virus-associated pathology in the salivary gland to day 28 post infection. Immunohistochemistry determined that HSPG was located in the lateral lobe duct region of the salivary glands. It has been suggested that human lactoferrin (hLF) may interfere with virus receptor attachment and is involved in inhibition of virus infection in vertebrate cells. To that end, the effects of bovine LF inhibition on virus attachment were compared between AR339 and TR339 in the mosquito cell line C7-10. Cytopathic effect was observed earlier and with greater intensity in TR339 infected monolayers when compared to AR339 infected monolayers. This suggests that bovine LF has an inhibitory effect on AR339 infection in invertebrate cells, possibly due to this variants use of HPSG for attachment.

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Biology Commons

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