Submitted to: Journal of Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2007
Publication Date: 3/18/2007
Citation: Lunney, J.K., Rowland, R., Nelson, E., Molina, R., Hermann, J., Kuhar, D.J., Christopher-Hennings, J., Leathers, V., Zimmerman, J. 2007. Do immune genes influence which pigs will have persistent Porcine Reproductive and Respiratory Syndrome virus (PRRSV) infections?. j.Immunology 178(45):5 Interpretive Summary:
Technical Abstract: This study, a part of the "Big Pig" project, was aimed at highlighting differences in immune responses between control pigs and pigs with PRRSV infections, from early times post inoculation (pi), 14 dpi, to long term persistent infections (as evidenced by viral RNA in tissues). Our goal is to identify immunological or virological correlates of persistent infection. Two-week old pigs (n=109) were inoculated with PRRSV ATCC VR-2332 and 56 age matched animals served as uninoculated controls. Sets of PRRSV infected and control pigs were euthanized at 2 week intervals through 203 dpi; blood and tissues were collected. RNA and cDNA was prepared from respiratory and regional mucosal tissues [lung, tracheobronchial lymph nodes (TBLN), tonsil] and assayed for expression of a panel of 23 immune markers, representing innate, T helper and regulatory genes. As expected, only low levels of interferon-gamma and certain innate immune genes were expressed by infected pigs early after inoculation. Our studies are aimed at determining whether there is a pattern of cytokine expression that might help predict which pigs will clear virus, and distinguish them from those that remain persistently infected. To date no pattern has been found with lung or TBLN; tests are continuing with tonsils and sera cytokine levels. We hope to identify regulatory pathways that would stimulate PRRSV immunity. Supported by USDA ARS and NRI PRRS CAP1 funds.