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United States Department of Agriculture

Agricultural Research Service

Title: The in Vitro Susceptibility of Macrophages to Porcine Reproductive and Respiratory Syndrome Virus Varies Between Genetically Diverse Lines of Pigs

Authors
item Vincent, Amy
item Thacker, Brad - IOWA STATE UNIVERSITY
item Halbur, Patrick - IOWA STATE UNIVERSITY
item Rothschild, Max - IOWA STATE UNIVERSITY
item Thacker, Eileen - IOWA STATE UNIVERSITY

Submitted to: Viral Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2005
Publication Date: September 1, 2005
Citation: Vincent, A.L., Thacker, B.J., Halbur, P.G., Rothschild, M.F., Thacker, E.L. 2005. The in vitro susceptibility of macrophages to porcine reproductive and respiratory syndrome virus varies between genetically diverse lines of pigs. Viral Immunology. 18:506-512.

Interpretive Summary: Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be responsible for large financial losses in the swine industry worldwide in spite of vaccination and control strategies. It is unknown if genetic differences in the host exist in susceptibility to PRRSV and if this variability can be exploited to help control this important disease. The objective of this study was to determine if a laboratory test using whole blood could be utilized to demonstrate genetic differences in susceptibility between distinct lines of pigs. This report suggests a genetic component for susceptibility to PRRSV at the cellular level exists and that the in vitro assay may be useful in predicting the overall susceptibility to PRRSV in large groups of animals.

Technical Abstract: Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be responsible for financial losses in the swine industry worldwide. It remains undetermined whether genetic variability of the host in susceptibility to PRRSV exists and if this variability can be exploited to help control this important disease. The objective of this study was to determine if an in vitro flow cytometry (FACS) assay which detects the percentage of monocyte-derived macrophages (MDMs) infected with PRRSV could be utilized to demonstrate genetic variability in the susceptibility between distinct lines of pigs. Over 400 growing pigs from six genetic lines maintained in a single commercial breeding herd were screened using an in vitro FACS assay. From this initial screening, two genetically diverse lines of pigs that were also divergent in their FACS results were selected for further study. An additional 264 pigs from these two lines were subsequently tested for in vitro susceptibility to PRRSV. As in the preliminary screening, the Large White line had significantly higher average percent positive MDMs over the Duroc-Pietrain synthetic line. This report suggests a genetic component for susceptibility to PRRSV exists and that the in vitro assay may be useful in predicting the relative susceptibility to PRRSV in large groups of animals.

Last Modified: 9/22/2014
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