Development of genetic markers in the non-structural protein 2 region of a US type 1 porcine reproductive and respiratory syndrome virus: implications for future recombinant marker vaccine development
Fang, Ying and Christopher-Hennings, Jane and Brown, Elizabeth and Liu, Haixia and Chen, Zhenhai and Lawson, Steven R. and Breen, Rachael and Clement, Travis and Gao, Xiaofei and Bao, Jingjing and Knudsen, David and Daly, Russell and Nelson, Eric,, 89, 3086-3096 (2008),
doi = https://doi.org/10.1099/vir.0.2008/003426-0,
publicationName = Microbiology Society,
issn = 0022-1317,
abstract= Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be a major problem in the pork industry worldwide. The limitations of current PRRSV vaccines require the development of a new generation of vaccines. One of the key steps in future vaccine development is to include markers for diagnostic differentiation of vaccinated animals from those naturally infected with wild-type virus. Using a cDNA infectious clone of type 1 PRRSV, this study constructed a recombinant green fluorescent protein (GFP)-tagged PRRSV containing a deletion of an immunogenic epitope, ES4, in the nsp2 region. In a nursery pig disease model, the recombinant virus was attenuated with a lower level of viraemia in comparison with that of the parental virus. To complement the marker identification, GFP and ES4 epitope-based ELISAs were developed. Pigs immunized with the recombinant virus lacked antibodies directed against the corresponding deleted epitope, but generated a high-level antibody response to GFP by 14 days post-infection. These results demonstrated that this recombinant marker virus, in conjunction with the diagnostic tests, enables serological differentiation between marker virus-infected animals and those infected with the wild-type virus. This rationally designed marker virus will provide a basis for further development of PRRSV marker vaccines to assist with the control of PRRS.,
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