title: Low-dose adenovirus vaccine encoding chimeric hepatitis B virus surface antigen-human papillomavirus type 16 E7 proteins induces enhanced E7-specific antibody and cytotoxic T-cell responses.
abstract: Induction of effective immune responses may help prevent cancer progression. Tumor-specific antigens, such as those of human papillomaviruses involved in cervical cancer, are targets with limited intrinsic immunogenicity. Here we show that immunization with low doses (10(6) infectious units/dose) of a recombinant human adenovirus type 5 encoding a fusion of the E7 oncoprotein of human papillomavirus type 16 to the carboxyl terminus of the surface antigen of hepatitis B virus (HBsAg) induces remarkable E7-specific humoral and cellular immune responses. The HBsAg/E7 fusion protein assembled efficiently into virus-like particles, which stimulated antibody responses against both carrier and foreign antigens, and evoked antigen-specific kill of an indicator cell population in vivo. Antibody and T-cell responses were significantly higher than those induced by a control adenovirus vector expressing wild-type E7. Such responses were not affected by preexisting immunity against either HBsAg or adenovirus. These data demonstrate that the presence of E7 on HBsAg particles does not interfere with particle secretion, as it occurs with bigger proteins fused to the C terminus of HBsAg, and results in enhancement of CD8(+)-mediated T-cell responses to E7. Thus, fusion to HBsAg is a convenient strategy for developing cervical cancer therapeutic vaccines, since it enhances the immunogenicity of E7 while turning it into an innocuous secreted fusion protein.
authors.affiliation: Gentherapie von Tumoren, Deutsches Krebsforschungszentum (DKFZ), Heidelberg, Germany.
authors.forename: Andrés
authors.initials: A
authors.lastname: Báez-Astúa
authors.forename: Elsa
authors.initials: E
authors.lastname: Herráez-Hernández
authors.forename: Natalio
authors.initials: N
authors.lastname: Garbi
authors.forename: Hilda A
authors.initials: HA
authors.lastname: Pasolli
authors.forename: Victoria
authors.initials: V
authors.lastname: Juárez
authors.forename: Harald
authors.initials: H
authors.lastname: Zur Hausen
authors.forename: Angel
authors.initials: A
authors.lastname: Cid-Arregui
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D019496:Cancer Vaccines / Q000008:administration & dosage / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D005822:Genetic Vectors; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D007114:Immunization; D008198:Lymph Nodes / Q000276:immunology; D018655:Lymphocyte Count; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology*; D027383:Papillomaviridae / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000097:blood / Q000276:immunology* / Q000517:prevention & control; D053918:Papillomavirus Vaccines; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D013045:Species Specificity; D013154:Spleen / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D002583:Uterine Cervical Neoplasms / Q000517:prevention & control; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D019496:Cancer Vaccines; D006514:Hepatitis B Surface Antigens; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D053918:Papillomavirus Vaccines; D011993:Recombinant Fusion Proteins; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; C059731:oncogene protein E7, Human papillomavirus type 16