Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: EXPANDING THE IMMUNE TOOLKIT FOR ASSESSING PIG HEALTH AND IMPROVING SWINE DISEASE AND VACCINE STUDIES Title: Probing Genetic Control of Swine Responses to PRRSV Infection: Current Progress of the PRRS Host Genetics Consortium

Authors
item Lunney, Joan
item Steibel, Juan -
item Reecy, James -
item Fritz, Eric -
item Rothschild, Max -
item Kerrigan, Maureen -
item Trible, B -
item Rowland, Raymond -

Submitted to: BioMed Central (BMC) Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 28, 2010
Publication Date: June 3, 2011
Citation: Lunney, J.K., Steibel, J.P., Reecy, J.M., Fritz, E., Rothschild, M.F., Kerrigan, M., Trible, B., Rowland, R.R. 2011. Probing Genetic Control of Swine Responses to PRRSV Infection: Current Progress of the PRRS Host Genetics Consortium. BioMed Central (BMC) Veterinary Research. 5(4):S30.

Interpretive Summary: Understanding the role of host genetics in resistance to porcine reproductive and respiratory syndrome virus (PRRSV) infection, and the effects of PRRS on pig health and related growth, are goals of the PRRS Host Genetics Consortium (PHGC). This manuscript gives an overview of the PHGC, the detailed planning process, and extensive samples collected from the 8 trials of 200 commercial crossbred pigs that have just been completed. These samples provide the basis for developing a deep phenotype from which to evaluate PRRS resistance/susceptibility. Results to date have verified that there is extensive variation in the pig’s response to virulent PRRSV infection as measured by viral level and weight gain. The current efforts to evaluate the genotype of all pigs using a 60,000 single-nucleotide polymorphism (SNP) chip will support the planned Genome-wide association studies (GWAS); these are now underway to identify alleles and chromosomal regions that regulate anti-PRRSV infection responses. Extensive gene and protein expression will provide additional markers for PRRS resistance/susceptibility. This continued phenotyping is possible because of the extensive PHGC planning, detailed sample inventory at KSU and BARC, and coordinated PHGC database. Overall, the PHGC project will enable researchers to discover and verify important genotypes and phenotypes that predict resistance/susceptibility to PRRSV infection. The availability of PHGC samples provides a unique opportunity to continue to develop deeper phenotypes on every PRRSV infected pig.

Technical Abstract: Background: Understanding the role of host genetics in resistance to porcine reproductive and respiratory syndrome virus (PRRSV) infection, and the effects of PRRS on pig health and related growth, are goals of the PRRS Host Genetics Consortium (PHGC). Methods: The project uses a nursery pig model to assess pig resistance/susceptibility to primary PRRSV infection. To date, 6 groups of 200 crossbred pigs from high health farms were donated by commercial sources. After acclimation, the pigs were infected with PRRSV in a biosecure facility and followed for 42 days post infection (dpi). Blood samples were collected at 0, 4, 7, 10, 14, 21, 28, 35 and 42 dpi for serum and whole blood RNA gene expression analyses; weekly weights were recorded for growth traits. All data have been entered into the PHGC relational database. Genomic DNAs from all PHGC1-6 pigs were prepared and genotyped with the Porcine SNP60 SNPchip. Results: Results have affirmed that all challenged pigs become PRRSV infected with peak viremia being observed between 4-21 dpi. Multivariate statistical analyses of viral load and weight data have identified PHGC pigs in different virus/weight categories. Sera are now being compared for factors involved in recovery from infection, including speed of response and levels of immune cytokines. Genome-wide association studies (GWAS) are underway to identify genes and chromosomal locations that identify PRRS resistant/maximal growth pigs and PRRS susceptible/reduced growth pigs. Conclusions: Overall, the PHGC project will enable researchers to discover and verify important genotypes and phenotypes that predict resistance/susceptibility to PRRSV infection. The availability of PHGC samples provides a unique opportunity to continue to develop deeper phenotypes on every PRRSV infected pig.

Last Modified: 9/20/2014
Footer Content Back to Top of Page