Determination of antigenic peptides within positive peptide pools. Direct IFN-γ Elispot assays were performed with single 18-mer F peptides at 20 μM. Only peptides of pools that were positive in previous assays were tested. The values are number of spots per 106 PBMC minus the number of spots in unstimulated PBMC. Donor VB-5, HLA-A2, B35,62, C4, DRB1*0401, DRB1*0403, DQB1*03; donor CE-3, HLA-A2, B40, DRB1*03,*0401, DQB1*02,03; donor VB-2, HLA-A1,29, B44,57, DRB1*0701, DRB1*1101, DQB1*03; donor CH-1, HLA-A2, B27,60, C2,3, DRB1*15,*16, DQB1*0502, DQB1*0602; and donor CE-4, HLA-A3,28, B7,35, DRB1*01, DQB1*05.