Recognition of naturally processed NY-ESO-1 by L9L-specific CD8+ T cells. ELISPOT assays with CD8+ T cells from NW924, a patient with spontaneous NY-ESO-1 immunity, presensitized with S9C (number of spots/50,000 cells) (A), and CD8+ T cells from PI-E01, a patient with no preexisting NY-ESO-1 immunity vaccinated with S9C and S11L, presensitized with L9L (number of spots/10,000 cells) (B). v.v. WT, wild-type vaccinia virus; v.v. ESO, vaccinia virus recombinant for full-length NY-ESO-1.