title: Induction of T cell responses by chimeric bacterial proteins expressing several copies of a viral T cell epitope.
abstract: A viral T cell epitope was genetically inserted within the periplasmic MalE protein of Escherichia coli in two different permissive insertion sites and resulting hybrid proteins were used to study the in vitro and in vivo immunogenicity of the foreign T cell epitope. Purified hybrid MalE proteins containing the T cell epitope 120-132 (PreS:T) from PreS2 region of hepatitis B virus HBsAg inserted alone or with its adjacent B cell epitope (132-145) were able to induce strong peptide-specific T cell responses in mice. In vitro stimulation of primed lymph node cells or specific T cell hybridomas by the hybrid proteins required processing of the inserted T cell epitope and was inhibited by antigen-presenting cells fixation. The inserted T cell epitope was presented in vitro, in association with appropriate major histocompatibility complex molecules, as efficiently as free synthetic peptide. The in vitro immunogenicity of MalE hybrid proteins was increased by inserting four tandemly repeated copies of PreS:T, either at site 133 or 303. These results were confirmed in vivo by comparing the proliferative responses of lymph node cells from DBA/1 mice primed with MalE hybrid proteins containing one or four copies of PreS:T. Thus, the use of MalE hybrid proteins expressing multiple copies of a given foreign T cell epitope allows the induction of peptide-specific T cell response with a lower dose of priming antigen.
authors.affiliation: Unités de Biologie des Régulations Immunitaires, Institut Pasteur, Paris, France.
authors.forename: R
authors.initials: R
authors.lastname: Lo-Man
authors.forename: P
authors.initials: P
authors.lastname: Martineau
authors.forename: M
authors.initials: M
authors.lastname: Hofnung
authors.forename: C
authors.initials: C
authors.lastname: Leclerc
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D029968:Escherichia coli Proteins; D005814:Genes, Viral; D006514:Hepatitis B Surface Antigens / Q000235:genetics*; D016056:Immunodominant Epitopes / Q000235:genetics; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D058619:Maltose-Binding Proteins; D051379:Mice; D008811:Mice, Inbred DBA; D009004:Monosaccharide Transport Proteins; D005810:Multigene Family; D033902:Periplasmic Binding Proteins; D011498:Protein Precursors / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006514:Hepatitis B Surface Antigens; D016056:Immunodominant Epitopes; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; C461599:maltose transport system, E coli; C050807:presurface protein 2, hepatitis B surface antigen