H2BC21 and neoplasm: Splenocyte samples from immunized or transgenic mice (from here on: antigen-specific mice) were stained with either 1) pH-2 tetramers exchanged with the specific peptides corresponding to the specificity induced by immunization or the transgenic TCR clone specificity (Table 1), or 2) pH-2 tetramers exchanged with an irrelevant peptide (predicted H-2b and H-2d ligand neo-peptides from syngeneic tumor cell lines, Supplementary Table 2).