Construction and application of an avian intestinal intraepithelial lymphocyte cDNA microarray (AVIELA) for gene expression profiling during Eimeria maxima infection.

Intestinal intraepithelial lymphocytes (IELs) are the primary immune effector cells in the gut and play a critical role in eliciting protective immunity to enteric pathogens such as Eimeria, the etiologic agent of avian coccidiosis. In this study, a microarray of genes expressed by intestinal IELs from Eimeria-infected chickens was constructed using the expressed sequence tag (EST) strategy. The avian intestinal IEL cDNA microarray (AVIELA) contained duplicates of 9,668 individual ESTs (6,654 known genes and 3,014 unique singletons of unknown identity) and was used to analyze gene expression profiles during primary and secondary Eimeria maxima infections. Following primary inoculation with E. maxima, the expression levels of 74 genes were significantly altered more than two-fold over the 3-day infection period (51 up-regulated, 23 down-regulated). Following secondary infection, the expression levels of 308 genes were significantly altered (62 up-regulated, 246 down-regulated). Pathway gene analysis indicated that many of the modulated genes were related to apoptosis, JAK/STAT, MAPK, interleukin, and TLR signaling pathways, and involving innate and adaptive immune responses. This chicken IEL microarray will provide a valuable resource for future transcriptional profiling of the genes involved in protective immunity to chicken enteric pathogens.