title: Recombinant E. coli efficiently delivers antigen and maturation signals to human dendritic cells: presentation of MART1 to CD8+ T cells.
abstract: The generation of tumour-specific cytotoxic T-lymphocyte (CTL) responses is the primary focus in the design of immunotherapeutic cancer vaccines. We have recently demonstrated generation of ovalbumin (OVA)-specific CTLs and tumour-protection in a murine tumour model using vaccination with dendritic cells (DCs) pulsed with E. coli expressing listeriolysin O (LLO) and OVA as a model antigen. In this system paraformaldehyde fixation of E. coli/LLO provided an additional safety feature without compromising vaccine efficacy. We therefore reasoned that paraformaldehyde-fixed recombinant E. coli expressing LLO would be an efficient vehicle for the delivery of human tumour antigens to human DCs. In the present study, we demonstrate that fixed E. coli expressing LLO are taken up efficiently by human monocyte-derived DCs (MoDCs) with minimal toxicity. As a consequence of the interaction with bacteria, human DCs undergo marked phenotypic and functional maturation. Furthermore, we show that fixed E. coli/LLO expressing the well-characterised human melanoma antigen, MART1, efficiently deliver the HLA-A2-restricted MART1(27-35) epitope for processing and presentation on human MoDCs, suggesting the potential of this system as a novel strategy for human tumour immunotherapy.
authors.affiliation: Cancer Research UK Molecular Oncology Unit, Imperial College London, Hammersmith Hospital, London, United Kingdom.
authors.forename: Kristen J
authors.initials: KJ
authors.lastname: Radford
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Jackson
authors.forename: Jui-Ho
authors.initials: JH
authors.lastname: Wang
authors.forename: Georges
authors.initials: G
authors.lastname: Vassaux
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Lemoine
mesh_terms: D017951:Antigen Presentation; D015703:Antigens, CD / Q000096:biosynthesis; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001427:Bacterial Toxins; D002454:Cell Differentiation; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D004274:DNA, Recombinant / Q000235:genetics; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology; D000939:Epitopes / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics*; D006684:HLA-DR Antigens / Q000096:biosynthesis; D006360:Heat-Shock Proteins / Q000378:metabolism; D006460:Hemolysin Proteins; D006801:Humans; D058965:MART-1 Antigen; D009000:Monocytes / Q000276:immunology; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D010587:Phagocytosis; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000951:Antigens, Neoplasm; D001427:Bacterial Toxins; D004274:DNA, Recombinant; D000939:Epitopes; D006684:HLA-DR Antigens; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D058965:MART-1 Antigen; C105787:MART-1-Melan-A(27-35) epitope; C548667:MLANA protein, human; D009363:Neoplasm Proteins; C038705:hlyA protein, Listeria monocytogenes