Identification of human minor histocompatibility antigens

Minor Histocompatibility antigen (mHag) disparities between HLA-matched bone marrow donors and recipients are a risk factor for Graft-versus-Host-Disease. Using T cell clones recognizing human mHag in the context of HLA, we have recently identified the HLA-A2.1 restricted HA-2 and the HLA-B7 restricted H-Y. The HLA-B7 restricted H-Y is encoded by the SMCY gene located on the human Y chromosome. It is unknown whether other H-Y mHag are also encoded by the same gene. Therefore we have isolated HLA-A2.1 and HLA-A1 restricted H-Y positive peptide fractions eluted from the respective HLA molecules that are purified by affinity chromatography. These fractions are currently being analysed by tandem mass spectrometry. At present, we are isolating and purifying the mHag HA-1. This non-sex linked antigen is significantly associated with Graft-versus-Host-Disease and may therefore be a suitable candidate for immunotherapy.