Peptide specificity of CD45-specific CTLs is mediated by CD8⁺ cells.

CTL line 2 was stimulated for 6 hours in the presence of brefeldin A, and T2 cells were pulsed with (A) control HLA-A0201 binding peptide HBV core (18-27) or with (B) P1218. Intracytoplasmic flow cytometry was used to demonstrate expression of IFN-γ in response to P1218 in CD8⁺ cells but not CD4⁺ cells.