Persistence of effector memory Th1 cells is regulated by the homeobox only protein Group1 Hopx-/-, Group2 Hopx+/-, Group3 Hopx+/+

Hopx appears to be needed for persistence of Th1 effector memory cells. IFN-gamma-producing Th cells are significantly reduced in Hopx-deficient mice compared to Hopx-expressing littermates and Hopx-deficient Th1 cells show a defective persistence upon adoptive transfer. Moreover, Hopx protects Th1 cells from Fas-mediated cell death in vitro. To further dissect the role of Hopx and to identify target genes of Hopx, we have performed transcriptome analysis to compare gene expression in Hopx-deficient versus Hopx-competent Th1 cells. In agreement with the role of Hopx in supporting survival of Th1 effector memory cells, anti-apoptotic cells were up-regulated and pro-apoptotic genes were down-regulated in Hopx-competent compared to Hopx-deficient Th1 cells. Gene expression profiles of Hopx-/- versus Hopx+/- and Hopx+/+ Th1 cells, respectively. Naïve Th cells were isolated from Hopx+/+, Hopx+/- and Hopx-/- OT2 mice and activated in vitro with their cognate antigen (OVA) under Th1 polarizing conditions. On day 6, viable cells were repeatedly activated. On day 12, viable cells were harvested and compared using Affymetrix 430A Version 2 GeneChip arrays. After total RNA extraction, reverse transcription, cDNA extraction, the biotinylated cRNA was transcribed, fragmented, and 15 µg cRNA hybridized in duplicates for each of the three groups to the GeneChip arrays. Group1: Hopx-/-, Group2: Hopx+/-, Group3: Hopx+/+. Lists of differentially regulated genes were created using High Performance Chip Data Analysis (HPCDA) with Bioretis database (http://www.bioretis-analysis.de). Worldwide data sharing is possible via Bioretis, please ask the authors.