AMES, Iowa - Research into Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is yielding new insights into fetal protection and the critical role of innate immunity, according to a study led by scientists at Iowa State University. The findings, stemming from work with a pregnant gilt model, could pave the way for improved breeding strategies to enhance resistance to this economically devastating swine disease.
PRRSV, first identified in the late 1980s, continues to inflict notable losses on the pork industry. Initial research focused on understanding the virus’s pathogenesis and developing vaccines. However, the virus’s high mutation rate and complex interactions with the host immune system have presented ongoing challenges. Early work by the research team explored the complex interplay between PRRSV infection and host gene expression pathways,as well as alternate anti-viral response mechanisms.
More recently, the team collaborated with researchers from Canada and the United States, including experts in reproductive physiology, to investigate the pregnant gilt model (PGM) of PRRSV infection. Researchers analyzed maternal and fetal tissues and gene expression to differentiate fetal outcomes: resistance (no detectable virus), resilience (survival despite viral presence), and susceptibility (high viral load and/or meconium staining). The data indicates that placental transfer of the virus is a key limiting factor in fetal infection, and that specific genes involved in innate immunity contribute to fetal protection.
The success of this research hinged on collaborative efforts, beginning with meticulous experimental design and sample collection. PRRSV infections were conducted in Biosafety Level 2 (BSL2) facilities, utilizing pigs sourced from current genetic lines provided by breeding companies. Dedicated teams were responsible for the careful collection of blood and tissue samples.
Data analysis was performed by students and postdoctoral researchers under the guidance of experienced scientists, with results securely stored in a database for ongoing evaluation. Manuscripts were then submitted for peer review. Funding for the project was provided by the National Pork Board, the USDA National Institute of Food and Agriculture (NIFA) and Agricultural Research Service (ARS), Genome Canada, affiliated universities, and the NC229 viral and NRSP-8 genome projects.
The NRSP-8 project, the National Animal Genome Research Program, is dedicated to advancing animal genomics research, with a particular focus on agricultural species.
