title: Enhancing the immunogenicity of bioengineered Listeria monocytogenes by passaging through live animal hosts.
abstract: Bioengineered Listeria monocytogenes can be used as a recombinant bacterial vaccine vector for the induction of strong cell-mediated immunity to passenger antigens. Listeria loses virulence after undergoing bioengineering techniques, thus decreasing its efficacy as a vaccine vector. We addressed this problem by examining the virulence, and the ability to induce CD8(+) T-cells, of Listeria monocytogenes vaccine strains before and after passaging through mice. We found that two in vivo passages are required to restore the induction of cell-mediated immunity to passenger antigens and maximum virulence to these strains. In addition, we found that after each passage, harvested bacteria must be cloned and checked for expression of the bioengineered gene to counter selection in favor of antigen loss mutants.
authors.affiliation: Department of Microbiology, University of Pennsylvania School of Medicine, 323 Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104-6076, USA.
authors.forename: Christian
authors.initials: C
authors.lastname: Peters
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Paterson
mesh_terms: D016915:AIDS Vaccines; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines; D001483:Base Sequence; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D016368:Frameshift Mutation; D015964:Gene Expression Regulation, Bacterial; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology*; D015750:Genes, gag; D015488:HIV Antigens / Q000235:genetics / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D008089:Listeria monocytogenes / Q000276:immunology* / Q000472:pathogenicity; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology*; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000235:genetics / Q000276:immunology*; D027383:Papillomaviridae / Q000235:genetics / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D012692:Serial Passage; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; D014774:Virulence
chemical_list: D016915:AIDS Vaccines; D000956:Antigens, Viral; D001428:Bacterial Vaccines; D015683:Gene Products, gag; D015488:HIV Antigens; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D014614:Vaccines, Synthetic; D014765:Viral Vaccines; C059731:oncogene protein E7, Human papillomavirus type 16