Transcriptomic analyis of the response of porcine PBMC to stimulation with concanavalin A

One of the top priorities of the swine industry worldwide is to decrease the susceptibility of its animals to infectious diseases. There is therefore now an increased focus on the production of more “robust” animals, which have lower susceptibility to a broad range of infectious diseases. One general measure of immune competence is the proliferative response of peripheral blood mononuclear cells (PBMC) to mitogenic stimulation. Concanavalin A (ConA) is a mitogen that predominantly stimulates T lymphocytes within the PBMC fraction of blood. T cells play a crucial role in both cell-mediated and humoral immunity. Variation between individuals in the magnitude of the proliferative response to ConA has been estimated to have moderate heritability, and quantitative trait loci (QTL) for this trait have been identified. However, detailed knowledge of the genomic pathways which coordinate this process in swine PBMC is currently lacking. The recent development of a high density oligonucleotide microarray for the pig research community means that it is now possible to study simultaneously the expression of a large proportion of genes from the pig genome. The objective of this research project was to profile gene expression in ConA-stimulated PBMC to identify the gene networks that control the cellular response to this mitogen. Peripheral Blood Mononuclear Cells (PBMC) from 4 individual biological replicates were used for this experiment. Separate cell aliquots from these animals were grown in culture with the mitogen concanavalin A for 4 different times: 0, 3, 20, and 68 hours. For the hybridization experiment, 3 separate direct comparisons of gene expression were made (0 v 3 hr, 0 v 20 hr and 0 vs 68 hr). Time-point samples from the same individual were always compared on the same array. Each comparison consisted of 8 hybridizations (4 biological replicates; 2 dye-swap technical replicates), making a total of 24 hybridizations.