An Attenuated Highly Pathogenic Chinese PRRS Viral Vaccine Confers Cross Protection to Pigs against Challenge with the Emerging PRRSV NADC30-Like Strain
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A novel PRRSV strain was isolated in China that was genetically similar to the NADC30 strain which is reported to have spread throughout China. The objective of the present study was to evaluate the cross-protective efficacy of the live vaccine TJM-F92 in young pigs against challenge with a NADC30-like strain, HN201605. Twenty-five PRRSV- and antibody-free pigs were randomly divided into the following five groups: Vac/ChA, Unvac/ChA, Vac/ChB, Unvac/ChB and the mock. The pigs in groups Vac/ChA and Vac/ChB were inoculated intramuscularly with 1 mL TJM-F92 (105.0 TCID50/mL). At 28 days post vaccination (0 days post challenge), groups Vac/ChA and Unvac/ChA were inoculated intranasally with 104.5 TCID50/mL PRRSV strain TJ F3 (2 mL/pig), while groups Vac/ChB and Unvac/ChB were inoculated, using the same route, with the same dose of the NADC30-like strain HN201605 F3. Protective effects of the PRRSV strain were observed in all pigs in the Vac/ChA and Vac/ChB groups. Neither high fever nor signs of clinical disease were observed through the experiment in these groups, whereas pigs in Unvac/ChA group exhibited serious clinical symptoms, pathological lesions, and weight loss. In Unvac/ChB group, pigs developed milder clinical symptoms, which demonstrated that the NADC30-like strain HN201605 had moderate pathogenicity. The results suggest that the MLV vaccine strain TJM-F92 is an effective and safe vaccine candidate for use in China.
KeywordsPorcine reproductive and respiratory syndrome virus (PRRSV) NADC30-like Vaccine Cross protection
The authors thank all the technicians who were involved in animal care and sample collection. The research results belonged to the Sinovet (Beijing) Biotechnology Co. Ltd.
HWZ, MQX, WW, DCJ, LC, BW, XW, YW, and NS performed the study, HWZ wrote the manuscript, and JXH and CXT participated in the collection of samples. HW and SCZ participated in revision of the manuscript. HW is the leader of the project. All authors read and approved the final manuscript.
Compliance with Ethics Standards
Conflict of interest
The authors declare that they have no competing interests.
Animal and Human Rights Statement
All animal experimental procedures have been reviewed and approved by the Animal Care and Use Committee of Sinovet (Jiangsu) Biotechnology Co. Ltd. (approval ID: SYXK(Su) 2013-0032). All pigs were supplied with water, food, and healthcare throughout the study period.
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