Identification of minor histocompatibility antigens by reverse immunology

Abstract

T-cell recognition of MiHA plays an important role in the GVT effect of allo-SCT. Selective infusion of T-cells reactive for hematopoiesis-restricted MiHA presented in the context of HLA-class I molecules may help to separate the beneficial GVT effects from GVHD after allo-SCT. To date, only a few MiHA that form attractive targets for adoptive immunotherapy have been characterized and the number of patients that can be treated with such MiHA-selective cell therapy remains limited. In this thesis we focused on __reverse immunology__ as an attractive strategy to identify clinically relevant MiHA and other T-cell epitopes. In this approach peptide predictions are the starting point and peptide candidates are subsequently screened for their capacity to induce a T-cell response. We investigated the feasibility of computational genome-wide prediction of hematopoietic MiHA and alternatively implemented mass spectrometry based HLA-peptidomics as source for candidate peptides. T-cells that reacted with these antigens were collectively isolated by MHC-tetramer pull down. Subsequently, the composition of MHC-tetramer positive T-cell populations was characterized and tested for reactivity against any of the predicted epitopes that was included in the initial MHC-tetramer panel. We generated an algorithm that could be exploited to selectively target T-cells specific for clinically relevant MiHA.