IFNG and neoplasm: HPV16 E6 tetramer-sorted lymphocytes from the different anatomic sites recognized an HLA-A∗0201-restricted E6 peptide regardless of the type of antigen-presenting cells used for stimulation as determined by IFN-γ production: by autologous tumor cells, by HLA-A∗0201 surrogate antigen-presenting cells pulsed with the small peptide, and by an HLA-A∗0201-matched human DC line transgenic for HPV16 E6.