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Application of reverse genetics to porcine reproductive and respiratory syndrome virus vaccinology

Hiep Lai Xuan Vu, University of Nebraska - Lincoln

Abstract

Porcine reproductive and respiratory syndrome virus (PRRSV) is endemic in most swine-producing countries, causing significant economic loss to swine producers. Current PRRSV vaccines are not adequately effective for control and eradication of the disease. The vaccines fail to elicit a robust neutralizing antibody (NAb) response in vaccinated pigs although NAbs can fully protect pigs from PRRSV infection. In addition, the vaccines do not allow serologically Differentiating Infected from Vaccinated Animals, a feature known as DIVA. A DIVA system is crucial for control and eradication of several important viral diseases in livestock. The objectives of this dissertation were: (i) to identify the mechanisms that PRRSV employs to evade NAb response and (ii) to develop a DIVA system for PRRSV. I indentified a PRRSV isolate called PRRSV-01 that elicited an unusually robust NAb response in infected pigs. Sequence analysis revealed that PRRSV-01 lacked two N-glycosylation sites in its envelope glycoproteins: one in GP3 and the other in GP5, both of which are consistently present in other PRRSV isolates. Through the gain-of-function studies, I found that the N-glycosylation sites in both GP3 and GP5 of PRRSV-01 were involved in subversion of NAb response. I also report here different approaches to develop a DIVA system for PRRSV. Through the use of reverse genetics, two mutant viruses were generated, both of which carried mutations in a conserved and immunodominant epitope (designated as epitope-201) located in the membrane protein. When experimentally inoculated into pigs, one of the mutant viruses was no longer able to elicit antibodies to the epitope-201. Consequently, the animals infected with this epitope-201 mutant virus were serologically differentiated from those infected with wt-PRRSV through the use of a blocking ELISA. Collectively, the results presented in this dissertation provide novel information for the development of more effective PRRSV vaccines.^

Subject Area

Biology, Genetics|Biology, Virology|Health Sciences, Immunology

Recommended Citation

Vu, Hiep Lai Xuan, "Application of reverse genetics to porcine reproductive and respiratory syndrome virus vaccinology" (2013). ETD collection for University of Nebraska - Lincoln. AAI3558016.
http://digitalcommons.unl.edu/dissertations/AAI3558016

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