Figure 2.

Affinity of the T cell clones for their cognate antigen. Peptides at various concentrations were pulsed onto autologous PBMCs for 2 h at 37°C. Subsequently the cells were irradiated (40Gy), unbound peptide was removed by extensive washing, and the cells were used as stimulators for the T cells. IFN-γ secretion by the T cells was measured 24 h later by ELISA. As shown for three T cell clones, all T cells described in this work recognized their cognate peptide (closed symbols) at a minimum concentration of 1–3 nM, whereas no response against PBMCs pulsed with an irrelevant peptide (open symbols) was observed.