Normal donor T-cell responses to putative EphA2-derived peptide epitopes

Responder CD4+ or CD8+ T cells were analyzed for reactivity against the HLA-A2+/DR4+ target cell line T2.DR4 pulsed with no peptides, or pulsed with irrelevant or EphA2-derived peptides. T cell reactivity against T2.DR4 cells pulsed with the HLA-A2-presented HIV-nef_190–198 epitope served as the CD8+ cell negative control, while HLA-DR4-presented Malarial circumsporozooite (CS)_326–345 epitope served as the CD4+ T cell negative control. These control values were subtracted from experimental determinations in order to determine EphA2-specific T cell responder spot numbers^a per 100,000 T cells, ^bA value of “0” reflects a frequency < 1/100,000 T cells. The appropriate HLA-A2 or −DR4 restricted nature of specific T cell recognition of peptides was validated by inclusion of anti-HLA-A2 or -DR4 mAb in replicate ELISPOT wells, respectively, with >90% inhibition of EphA2-specific recognition observed (data not shown). Values significantly (p < 0.05) elevated over T2.DR4+ control peptide values are italicized.