#16-181

Progress

Date Full Report Received

11/26/2019

Date Abstract Report Received

11/26/2019

Investigation

Institution:
Primary Investigator:

In collaboration with researchers at the University of Missouri, we demonstrated that genetically edited pigs lacking CD163 are completely resistant to infection with porcine reproductive and respiratory syndrome virus (PRRSV). This is the first clear demonstration that PRRS can be prevented. The use of the CD163-modified pig in swine production means that PRRS-specific control measures, including vaccines, diagnostics, and barn filtration, will no longer be needed. As part of normal homeostasis, CD163 participates in the removal of excess hemoglobin from the blood and modulation of the inflammatory response after tissue damage or infection. The purpose of this work is to identify small regions in CD163, which can be removed or altered, which will protect a pig from infection without affecting other important biological functions of CD163. The first part of the project utilized a culture system for testing the susceptibility of cells expressing modifications in CD163. Infection of cultured cells identified three candidate constructs for further development in pigs. All modifications were predicted to produce resistance against common strains of PRRSV. The CRISPR/Cas9 methodology was successfully applied for the construction of CD163-modified embryos. Because this is new technology, several challenges were encountered. Therefore, additional funding was obtained from USDA NIFA to increase the number and efficiency of CD163-edited pigs, which can be used for infection studies.

Contact Information: Raymond (Bob) Rowland, College of Veterinary Medicine, Kansas State University, email: browland@vet.k-state.edu

Key Findings:
• PRRSV infection can be prevented in cells by making small mutations in CD163
• Modified CD163 shows resistance to PRRSV-1 and PRRSV-2 isolates
• CRISPR-modified pig embryos were successfully prepared and evaluated for mutations