title: Recombinant Salmonella typhimurium strains that invade nonphagocytic cells are resistant to recognition by antigen-specific cytotoxic T lymphocytes.
abstract: To address the question of whether Salmonella-infected nonphagocytic cells could serve as target cells for recognition by antigen-specific, major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTL), four recombinant Salmonella typhimurium constructs that expressed full-length, or fragments of, influenza A virus nucleoprotein (NP) were made. The bacteria were shown to infect Chinese hamster ovary (CHO) cells. Appropriate major histocompatibility complex restriction molecules, HLA-B27 and H-2 Db, were transfected into CHO cells, which were then infected with recombinant S. typhimurium and used as targets for NP-specific CTL. The cells in which NP was expressed by intracellularly replicating bacteria were not lysed by NP-specific CTL, although they were killed when appropriate influenza A virus or peptides were used. Thus, S.typhimurium bacteria within nonphagocytic cells were resistant to CTL recognition. In contrast to these results, mice infected with recombinant S.typhimurium that expressed fragments of NP in the periplasm were primed for NP-specific CTL responses. The results indicate that CTL responses specific to Salmonella antigens can be generated, but the bacteria may be safe from the CTL attack once they have entered the nonphagocytic cells.
authors.affiliation: Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: X M
authors.initials: XM
authors.lastname: Gao
authors.forename: J P
authors.initials: JP
authors.lastname: Tite
authors.forename: M
authors.initials: M
authors.lastname: Lipscombe
authors.forename: S
authors.initials: S
authors.lastname: Rowland-Jones
authors.forename: D J
authors.initials: DJ
authors.lastname: Ferguson
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
mesh_terms: D000818:Animals; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D051379:Mice; D008969:Molecular Sequence Data; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D016601:RNA-Binding Proteins; D011995:Recombination, Genetic; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014162:Transfection; D014758:Viral Core Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology
chemical_list: C048842:NP protein, Influenza A virus; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D016601:RNA-Binding Proteins; D014758:Viral Core Proteins