Lack of spontaneous T-cell responses against high-affinity HLA-A2–binding peptides. PBLs from 8 healthy individuals and 8 patients with late-stage breast cancer were analyzed. All individuals were HLA-A2 positive. The peptides bcl₈₅ (A), bcl₂₁₈ (B), bcl₂₂₀ (C), bcl₂₂₂ (D), bcl₂₂₄ (E), and bcl₁₂₄ (F) were examined. T lymphocytes were stimulated once with peptide before being plated at 10⁵ cells per well in triplicates either without or with peptide. The average number of peptide-specific spots (after subtraction of spots without added peptide) was calculated for each patient using the ImmunoSpot Series 2.0 Analyzer (CTL Analyzers). All individuals were nonresponding. Responders (defined as average number of antigen-specific spots ± 1/2 standard deviation < 25 per 10⁵ lymphocytes) are indicated by , whereas indicates nonresponding individuals.