Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2005
Publication Date: 1/14/2006
Citation: Lunney, J.K., Petry, D., Boyd, P., Kuhar, D.J., Blankenship, E., Johnson, R. 2006. Differential Immune Gene And Protein Expression In Pigs With High And Low Responses To Porcine Reproductive And Respiratory Syndrome Virus (PRRSv) Infection. International Plant and Animal Genome XIV Conference. p.584. Available: http://www.intl-pag.org/14/abstracts/PAG14_P584.html
Technical Abstract: Duroc/Hampshire crossbred pigs (100) and NE Index line pigs (100) were infected with PRRSv and evaluated for immune factors that potentially control resistance/susceptibility to infection. Controls (100/line) were uninfected littermates to each infected pig. Viremia (V), weight change (WT'), and rectal temperature at 0, 4, 7, and 14 days post-infection (dpi) were recorded. Lung, bronchial lymph node (BLN), and blood were collected at necropsy (14dpi). Line differences, and line by treatment interactions across days, indicated genetic variation in responses to PRRSv (Petry, J Anim Sci. 83: 1494, 2005). Principal component analyses were used to rank pigs for phenotypic response to PRRSv. Pigs classed as low (L) responders had high WT', low V, and few lung lesions; high (H) responders had low WT', high V, and many lesions. RNA from frozen lung and BLN tissue of the 7 highest and lowest responders per line, and from each of their littermates, were extracted. cDNA expression of 12 specific innate and Th1 immune markers was evaluated in a 2*2*2 factorial treatment design. Significant under-expression for certain immune genes of 14 dpi L pigs, relative to controls, was detected in lung and BLN, particularly in the NE Index line. Serum levels of immune cytokines affirmed the lung differences. High pre-infection serum levels of interleukin-8, was significantly associated with PRRSV resistant, L pigs. Following infection, low expression of interferon-gamma in cDNA and serum was also correlated with resistance. These data are critical for genetic association studies to fine map candidate genes and determine causative alleles.