title: Lactococcus lactis: high-level expression of tetanus toxin fragment C and protection against lethal challenge.
abstract: To determine if the food-grade bacterium Lactococcus lactis holds promise as a vaccine antigen delivery vector we have investigated whether this bacterium can be made to produce high levels of a heterologous protein antigen. A regulated expression system has been developed which may be generally suitable for the expression of foreign antigens (and other proteins) in L. lactis. The system utilizes the fast-acting T7 RNA polymerase to transcribe target genes, and provides the first example of the successful use of this polymerase in a Gram-positive bacterium. When the performance of the expression system was characterized using tetanus toxin fragment C (TTFC) up to 22% of soluble cell protein was routinely obtained as TTFC. Mice immunized subcutaneously with L. lactis expressing TTFC were protected from lethal challenge with tetanus toxin. These results show for the first time that L. lactis is able to express substantial quantities of a heterologous protein antigen and that this organism can present this antigen to the immune system in an immunogenic form.
authors.affiliation: University of Cambridge, Department of Pathology, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Wells
authors.forename: P W
authors.initials: PW
authors.lastname: Wilson
authors.forename: P M
authors.initials: PM
authors.lastname: Norton
authors.forename: M J
authors.initials: MJ
authors.lastname: Gasson
authors.forename: R W
authors.initials: RW
authors.lastname: Le Page
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005822:Genetic Vectors; D013294:Lactococcus lactis / Q000235:genetics*; D051379:Mice; D008808:Mice, Inbred CBA / Q000276:immunology; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D013742:Tetanus / Q000517:prevention & control; D013744:Tetanus Toxin / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D013745:Tetanus Toxoid; D014614:Vaccines, Synthetic; D014764:Viral Proteins
chemical_list: D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D013744:Tetanus Toxin; D013745:Tetanus Toxoid; D014614:Vaccines, Synthetic; D014764:Viral Proteins; C040635:tetanus toxin fragment C; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases