Technical Abstract: To further investigate the potential role of '-tocopherol in maintaining immuno-homeostasis in bovine cells (Madin-Darby bovine kidney epithelial cell line), we undertook in vitro experiments using recombinant TNF-a as an immuno-stimulant to simulate inflammation response in cells with and without '-tocopherol pretreatment. Using microarray global profiling and IPA (Ingenuity Pathways Analysis, Ingenuity® Systems, www.ingenuity.com) data analysis on TNF-'-induced gene perturbation in those cells, we focused on determining whether '-tocopherol treatment of normal bovine cells in a standard cell culture condition could modify the immune response of cells induced by a TNF-' challenge. When three datasets were filtered and compared using IPA, there were a total of 1750 genes in all three datasets for comparison: 97 genes were common to all three datasets; 615 genes were common to at least two datasets; there were 261 genes unique in the TNF-' challenge, 399 genes were unique in the '-tocopherol treatment, and 378 genes were unique in the '-tocopherol plus TNF-a treatment. The TNF-' challenge induced significant changes in gene expression. Many of the genes induced by TNF-' are related to the immune and inflammatory responses of cells. The results of the IPA data analysis showed that '-tocopherol pretreatment of cells modulated the cells’ response to the TNF-' challenge. In most of the canonical pathways, '-tocopherol pretreatment showed an antagonistic effect against the TNF-'-induced proinflammatory responses. We concluded that '-tocopherol pretreatment has a significant antagonistic effect that modulates the cell’s response to TNF-' challenges by altering the gene expression activities of some important signaling molecules.