Establishing value/utility of soluble CD163 as a biomarker for predicting PRRS-induced disease severity in swine herds

Project 17-011 - Lead Researcher: Dr. John Harding, University of Saskatchewan

The swine industry is economically burdened by porcine reproductive and respiratory syndrome (PRRS) and PRRSV-induced coinfections partly due to the lack of fully protective vaccines and also by the absence of a reliable method to distinguish disease-susceptible (moderately to severely affected by disease) vs disease-resilient (only mildly affected by disease) pigs. Previous research has shown that PRRSV uses the CD163 receptor to infect pigs. Levels of CD163 on the surface of macrophages (immune cells) increase and decrease through processes of expression and shedding. When shed, soluble CD163 (sCD163) is released into the bloodstream.  The research team is proposing to evaluate if the bio-marker sCD163 can be used to predict how severely PRRSV will affect the health of a pig. The project will quantify the level of soluble CD163 in a large number of blood samples that have been collected from pigs challenged with a very high-impact PRRSV, and pigs challenged with PRRSV in addition to multiple other diseases. The researchers will also establish baseline sCD163 levels in pigs by screening healthy pigs from Ontario farms in collaboration with their industry partner, PigGen Canada.  Using all of the data collected, the researchers will investigate if there is a correlation between the level of sCD163 in the blood and the disease severity/resilience of pigs infected with PRRSV. The overall project goal is to develop a low-cost tool to assist in the selection of disease resilient pigs to help combat PRRSV and related co-infections in breeding and feeding herds.