Identifying genes for intestinal nematode resistance using transcriptional profiling

Gene expression was compared between resistant and susceptible Perendale lambs that had either never been exposed to gastrointestinal nematode challenge (had a naïve immune system with respect to parasites) or had been naturally challenged on pasture with nematodes. Only a small number of genes were differentially expressed between the naive resistant and susceptible animals, but many genes were differentially expressed between the resistant and susceptible challenged animals. The differentially expressed genes were involved in a variety of biological processes, most notably the immune response, the stress response and gene regulation via chromatin remodelling. The transcriptional profiling experiments also detected gene expression differences in the Ovar-DQA1 gene between resistant and susceptible challenged animals. A null allele of this gene was demonstrated to be associated with susceptibility to gastrointestinal parasites in some, but not all populations. This allele is not thought to be causal for susceptibility.