Publication Date:
2009-11-20
Description:
Abstract 685 Allogeneic stem cell transplantation (allo-SCT) followed by donor lymphocyte infusion (DLI) is used as a curative treatment for patients with malignant diseases. Donor derived T cells mediate graft versus tumor responses by targeting minor histocompatibility antigens (mHags) that are encoded by patient specific single nucleotide polymorphisms (SNPs). Various approaches have been applied for mHag discovery resulting in the characterization of more than 20 mHags. However, restriction to specific HLA types and unfavourable gene expression strongly limits the number of clinically relevant mHags. Recently, it has been demonstrated that whole genome association scanning (WGAs) can be a tool for mHag identification. Here, we present WGAs as a powerful method for high throughput identification of new mHags. From 2 patients that entered complete remission with limited graft versus host disease after allo-SCT and DLI, activated T cells were cloned by flowcytometric cell sorting. After expansion, 232 stably growing T cell clones were obtained. Patient specific recognition in the absence of donor recognition was demonstrated for 78 clones. By using blocking antibodies and a test panel consisting of partially HLA matched EBV-transformed B cell lines (EBV-LCL), we demonstrated that these 78 T cell clones comprised 20 unique mHag reactivities which could be identified to be restricted to HLA-A*02 or B*07. Since WGAs is based on a balanced segregation of test cells in a positive and a negative group, 15 T cell clones were selected recognizing mHags with population frequencies between 20% to 80% for further analysis. To perform WGAs, a test panel was generated containing 80 HLA-A*02 and B*07 positive EBV-LCL for testing of recognition by all selected T cell clones using Interferon-γ Elisa. In parallel, all EBV-LCL were genotyped for 1 million SNPs using bead arrays. All SNP genotype patterns were combined with each individual T cell recognition pattern. The level of matching between both patterns was statistically analyzed using Fisher's exact test, resulting in p-values indicating the significance of association. Significant association (p-value
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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