title: T-helper epitopes identified within the E6 transforming protein of cervical cancer-associated human papillomavirus type 16.
abstract: The E6 oncoprotein of human papillomavirus type 16 (HPV16 E6) produced by tumor cells of HPV16-associated cervical carcinoma is poorly immunogenic in patients, but nonetheless is a tumor-specific antigen to which therapeutic vaccine strategies may be directed. To investigate the subunit immunogenicity of E6 protein at the T-helper cell level, we immunized mice with overlapping peptides spanning the entire 158 amino acid sequence. Two peptides recalled a proliferative response in lymph node cells (LNC) from C57BL/6 (H-2b)-immunized mice. One of these peptides also recalled proliferative responses in the context of 5/5 other major histocompatibility complex (MHC) class II haplotypes, indicating a "promiscuous" T-epitope. Minimal consensus motif analysis identified the epitopes as 60VYRDGNPYA68 and 98GYNKPLCDLL107. LNC from mice immunized with T-epitope proliferated in response to challenge with whole E6 protein. Immunization with E6 T-epitopes linked to B-epitopes of HPV16 E7 protein elicited specific antibody indicating that T-cells recognizing the T-epitopes provided cognate "help" for B-cells. LNC from mice co-immunized with E6 T-epitope and the major T-helper epitope of HPV16 E7 (48DRAHYNI54) proliferated comparably when challenged with the peptides individually indicating co-dominance of the two T-epitopes. The findings have implications for incorporation of E6 into a therapeutic vaccine.
authors.affiliation: Centre for Immunology and Cancer Research, University of Queensland Department of Medicine, Princess Alexandra Hospital, Brisbane, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Azoury-Ziadeh
authors.forename: K
authors.initials: K
authors.lastname: Herd
authors.forename: G J
authors.initials: GJ
authors.lastname: Fernando
authors.forename: I H
authors.initials: IH
authors.lastname: Frazer
authors.forename: R W
authors.initials: RW
authors.lastname: Tindle
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D006801:Humans; D007114:Immunization; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D027383:Papillomaviridae / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000276:immunology / Q000821:virology; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D012097:Repressor Proteins; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014412:Tumor Virus Infections / Q000276:immunology / Q000821:virology; D002583:Uterine Cervical Neoplasms / Q000276:immunology / Q000821:virology*; D014765:Viral Vaccines / Q000276:immunology
chemical_list: C068651:E6 protein, Human papillomavirus type 16; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D010455:Peptides; D012097:Repressor Proteins; D014765:Viral Vaccines; C059731:oncogene protein E7, Human papillomavirus type 16