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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 2/28/2006 Publication Date: 6/29/2006 Citation: Lunney, J.K. 2006. Genomic evaluation of host-pathogen interactions. Meeting Abstract. Available: http://lotus5.vitamib.com/hnb/eadgene/eadgene.nsf/all/20008C698A0625A2C125712F00738D30 Interpretive Summary: Technical Abstract: Genomics promises to provide invaluable tools for improving animal health and preventing disease. Our laboratory’s efforts have focused on using functional genomic approaches to identify immune and genetic factors that lead to healthy, disease resistant pigs. We aim to determine critical markers that endow pigs with innate resistance to infection or that control protective immune responses to pathogens. Using functional genomics we have identified innate immune markers required for effective responses against porcine reproductive and respiratory syndrome (PRRS), the most economically significant disease facing the swine industry today. Immune responses to both type 1 and type 2 PRRSV infections and vaccinations have been evaluated. Despite the adjuvant effect of interferon-alpha (IFNA) on in vitro IFNG responses to type 2 vaccination, there were no apparent alterations in immune gene expression nor improved protection against viral challenge. This response agrees with our recent genetic resistance to type 2 PRRS studies with University Nebraska-Lincoln scientists. Those results indicated that there are significant differences in lung and bronchial lymph node innate and T helper 1 (Th1) immune gene expression patterns in pigs with high or low PRRSV burden. These correlated with high pre-infection protein levels of the innate cytokine, interleukin-8 (IL8), in pigs with better resistance to PRRSV. Additionally resistant pigs had faster response to the infection but unexpectedly lower IFNG responses than susceptible pigs. Differential tissue analyses of immune gene expression are underway to determine factors involved in controlling/enabling long-term PRRSV persistence (up to 210 days post infection). Comparisons of immunity to the fast effective, IFNG-dominated Th1 response to the food borne parasite, Toxoplasma gondii, may help reveal key factors that divert anti-PRRSV immunity. Separate studies with Iowa State and ARS NADC scientists on Salmonella infections have identified some key regulators for this foodborne bacterial infection. Using a combination of microarrays and real-time gene expression assays local mucosal immune regulatory factors are being identified. Overall these studies should help to select pigs with genetically encoded resistance to specific infections and to the design of improved vaccines or novel biotherapeutics. |
