A comparison of gene expression in tolerated and rejected islet grafts by gene microarray analysis

Background. It has recently been demonstrated that donor-specific tolerance to MHC-matched minor-antigen-mismatched islet allografts in diabetic NOD mice could be induced by simultaneous islet and bone marrow transplantation preventing both graft rejection and recurrence of autoimmunity. Despite the presence of tolerance and good graft function mononuclear cell infiltration surrounding the islet was found in tolerated grafts. To elucidate the differences between these mononuclear infiltrates in the presence of tolerance and destructive mononuclear infiltrates during graft rejection as well as their influence on intragraft gene expression, tolerated islet grafts from the described model and rejected islet grafts from untreated animals were subjected to gene expression studies. <br>Methods. Gene expression analysis in tolerated and rejected islet grafts was performed by using Affymetrix Murine U74A oligonucleotide arrays. Real-time PCR and RNase protection assay on selected genes were performed to confirm the results of microarray analysis. <br>Results. Of over 12,000 genes studied, 57 genes were expressed at consistently higher levels in tolerated islet grafts, and 524 genes in rejected islet grafts. Genes from a variety of different functional clusters were found to be different between rejected and tolerated grafts. In the rejected islet grafts, a number of T cell surface markers (e.g., CD3, CD8) and of cytotoxicity-related genes (e.g., granzyme B and Fas ligand) were highly expressed. Also in the rejected grafts, a number of cytokines and chemokines and their receptors (e.g., IL-1b, IFN-g, MIG, RANTES) were found at high levels. The differential expression of selected genes found by microarray analysis was also confirmed by real-time PCR and RNase protection assay. <br>Conclusion. In our studies, infiltrating mononuclear cells in rejected and tolerated islet grafts showed differential expression in a number of genes belonging to different functional clusters. Gene microarray analysis can be used to detect gene expression differences representative of the biologic mechanisms of tolerance and rejection and thereby provide us a new tool for the discovery of genes that can be used in immune monitoring and as target for new medical therapies for the treatment of rejection.

Author dc:creator

• Berg, Tobias

Contributors dc:contributor

• Reincke, Martin

• Transplantation immunology
• islet transplantation
• microarray
• immune tolerance
• chemokines

Repository record source_url

https://freidok.uni-freiburg.de/data/1948

OAI identifier oai:identifier

oai:freidok.uni-freiburg.de:1948