Natural processing and presentation of the HOM-MEL-40/SSX2-derived p103-111 peptide. (A) HLA-A*0201 restriction of SSX2-derived p103-111 stimulated CD8+ T-cells. COS7/A2 cells transfected with HOM-MEL-40/SSX2 were used as targets and EGFP-transfected cells served as a negative control in the ELISPOT assay. The reaction was blocked by adding the anti-pan human MHC-I antibody (clone W6/32) or the anti-HLA-A*02 antibody (clone BB7.2). (B) Recognition of the HLA-A*02 positive, SSX2 positive SK-MEL-37 cell line. The recognition of the cell line by SSX2-derived p103-111 stimulated T-cells was demonstrated by ELISPOT assay. The effect of a pretreatment of the SK-MEL-37 cells with IFN-gamma was tested. In order to block the reaction against SK-MEL-37, the anti-pan human MHC-I antibody (clone W6/32) was added. The tumor cell lines BT 549 (HLA-A*02+/SSX2-), T47D (HLA-A*02-/SSX2+) and ZR7530 (HLA-A*02-/SSX2-) were used as negative controls.