title: Immunization with Human Papillomavirus 16 L1+E2 Chimeric Capsomers Elicits Cellular Immune Response and Antitumor Activity in a Mouse Model.
abstract: Development of cervical cancer is associated with persistent infections by high-risk human papillomavirus (HPV). Although current HPV L1-based prophylactic vaccines prevent infection, they do not help to eliminate prevalent infections or lesions. Our aims were (i) to generate a vaccine combining prophylactic and therapeutic properties by producing chimeric capsomers after fusion of the L1 protein to different fragments of E2 from HPV 16, and (ii) to evaluate their capacity to generate an antitumoral cellular response, while conserving L1 neutralizing epitopes. Chimeric proteins were produced in Escherichia coli and purified by glutathione S-transferase (GST)-affinity chromatography. Their structure was characterized using size exclusion chromatography, sucrose gradient centrifugation, electron microscopy, and anti-L1 enzyme-linked immunosorbent assay. All chimeric proteins form capsomers and heterogeneous aggregates. One, containing part of the carboxy-terminal domain of E2 and its hinge region (L1Δ+E2H/NC, aa 206-307), conserved the neutralizing epitope H16.V5. We then evaluated the capacity of this chimeric protein to induce a cytotoxic T-cell response against HPV 16 E2. In (51)Cr release cytotoxicity assays, splenocytes from C57BL/6 immunized mice recognized and lysed TC-1/E2 cells, which express and present endogenously processed E2 peptides. Moreover, this E2-specific cytotoxic response inhibited the growth of tumors of TC-1/E2 cells in mice. Finally, we identified an epitope (aa 292-301) of E2 involved in this cytotoxic response. We conclude that the L1Δ+E2H/NC chimeric protein produced in bacteria can be an effective and economically interesting candidate for a combined prophylactic and therapeutic vaccine that could help eliminating HPV16-positive low-grade cervical lesions and persistent viral infections, thus preventing the development of lesions and, at the same time, the establishment of new infections.
authors.affiliation: 1 Department of Molecular Biology and Biotechnology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, Mexico .|2 Laboratory of Virus and Cancer, Division of Basic Research, Instituto Nacional de Cancerología-SS , Mexico City, Mexico .
authors.forename: Gabriela
authors.initials: G
authors.lastname: López-Toledo
authors.affiliation: 3 Division of Genome Modifications and Carcinogenesis, German Cancer Research Center (DKFZ) , Heidelberg, Germany .
authors.forename: Lysann
authors.initials: L
authors.lastname: Schädlich
authors.affiliation: 2 Laboratory of Virus and Cancer, Division of Basic Research, Instituto Nacional de Cancerología-SS , Mexico City, Mexico .
authors.forename: Ángel Josabad
authors.initials: ÁJ
authors.lastname: Alonso-Castro
authors.affiliation: 4 Laboratory of Immunobiology, Facultad de Estudios Superiores Zaragoza , Unidad de Investigación en Diferenciación Celular y Cáncer, UMIEZ, UNAM, Mexico City, Mexico .|5 Laboratory of Immunology and Cancer, Unidad de Investigación Médica en Enfermedades Oncológicas , CMN SXXI, IMSS, Mexico City, Mexico .
authors.forename: Alberto
authors.initials: A
authors.lastname: Monroy-García
authors.affiliation: 5 Laboratory of Immunology and Cancer, Unidad de Investigación Médica en Enfermedades Oncológicas , CMN SXXI, IMSS, Mexico City, Mexico .|6 Department of Immunology, Escuela Nacional de Ciencias Biológicas , IPN, Mexico City, Mexico .
authors.forename: Rosario
authors.initials: R
authors.lastname: García-Rocha
authors.affiliation: 1 Department of Molecular Biology and Biotechnology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, Mexico .|2 Laboratory of Virus and Cancer, Division of Basic Research, Instituto Nacional de Cancerología-SS , Mexico City, Mexico .
authors.forename: Miriam C
authors.initials: MC
authors.lastname: Guido
authors.affiliation: 3 Division of Genome Modifications and Carcinogenesis, German Cancer Research Center (DKFZ) , Heidelberg, Germany .
authors.forename: Lutz
authors.initials: L
authors.lastname: Gissmann
authors.affiliation: 1 Department of Molecular Biology and Biotechnology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México , Mexico City, Mexico .|2 Laboratory of Virus and Cancer, Division of Basic Research, Instituto Nacional de Cancerología-SS , Mexico City, Mexico .
authors.forename: Alejandro
authors.initials: A
authors.lastname: García-Carrancá
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology*; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D004195:Disease Models, Animal; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D052162:Human papillomavirus 16 / Q000254:growth & development / Q000276:immunology; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009856:Oncogene Proteins, Viral / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D030361:Papillomavirus Infections / Q000188:drug therapy / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D053918:Papillomavirus Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000821:virology
chemical_list: D000956:Antigens, Viral; D036022:Capsid Proteins; D004268:DNA-Binding Proteins; C054855:E2 protein, Human papillomavirus type 16; D000939:Epitopes; D009856:Oncogene Proteins, Viral; D053918:Papillomavirus Vaccines; D011993:Recombinant Fusion Proteins; C063317:L1 protein, Human papillomavirus type 16