Identification of a naturally processed HLA A0201-restricted viral peptide from cells expressing human papillomavirus type 16 E6 oncoprotein

Human papillomavirus (HPV) DNA encoding the oncogenic proteins E6 and E7 is usually retained in cervical carcinomas, implicating these proteins as potential target antigens for immune recognition in this virally associated tumor. We have characterized endogenously processed peptides eluted from major histocompatibility complex class I molecules in cells infected with a recombinant vaccinia expressing the HPV-16 E6 oncoprotein. The reverse-phase chromatography profile of peptides eluted from isolated HLA-A0201 molecules in cells expressing the E6 oncoprotein differs from that of cells not expressing E6. Sequential Edman degradation of novel peaks found in the peptide profiles from cells expressing HPV-16 E6 led to the identification of a naturally processed HLA-A0201-restricted E6 peptide of sequence KLPQLCTEL. This approach has allowed the identification of a viral peptide which is processed and presented by cells expressing the E6 oncoprotein and is a likely target for cytotoxic T lymphocyte recognition in HLA-A0201-positive patients.