Porcine genome-wide gene expression in response to tetanus toxoid vaccine.

The very early in vivo response to immune stimuli was studied using tetanus toxoid as a model antigen known to induce Th1 and Th2 responses. Eighteen weaning piglets were vaccinated subcutaneously with tetanus toxoid. Leukocyte RNAs were isolated from samplings before and 2, 4, 8, and 24 hours after vaccination. After competitive hybridization of a 13297 porcine 70-mer oligo microarray (Qiagen-Operon NRSP8), subsequent image analysis and normalization, the data was analysed using analyses of variance (ANOVA) to identify genes regulated due to vaccination (ANOVA, p < or = 0.05; corresponding to false discovery q < or = 0.12). Of 8240 probes representing genes expressed in leukocytes, 1289 genes showed differential expression. Results were exemplarily confirmed by real-time PCR. Holistic expression data was clustered to six prominent groups of genes with similar changes in expression patterns using a k-means algorithm. To get more insight into functional and structural components and impact of the genes represented in each cluster, the EASE score was used to identify Gene Ontology functional categories. The results showed that in vivo significant changes of expression profiles of peripheral blood mononuclear cells (PBMCs) occurred very early after immune stimuli. These alterations concerned genes of pathways related to immune response as well as other metabolic and regulatory pathways including ATP/energy metabolism, transcription, structural molecule activity, biosynthesis, and metabolism. The analysis reveals new functional candidate genes for traits related to immune responsiveness and also provides new insight into the interaction of immune response, and metabolic and endocrine status. This will facilitate a better understanding of the relationship between immune and performance traits.