title: Genetic requirements for salmonella-induced cytopathology in human monocyte-derived macrophages.
abstract: Infection of human macrophages with Salmonella enterica serovar Typhimurium or Salmonella enterica serovar Dublin produces delayed cytotoxicity characterized by cell detachment and associated apoptosis. Using a site-specific mutant in the SpvB active site, we verify that the ADP-ribosylation activity of SpvB is required for delayed cytotoxicity in human macrophages infected with Salmonella: SipB and the type III protein secretion system (TTSS) encoded by Salmonella pathogenicity island 1 (SPI1) are not involved, whereas the SPI2 TTSS is absolutely required for SpvB-dependent cytotoxicity. Furthermore, we show that infection of macrophage cultures with wild-type or sipB mutant bacteria led to a complete loss of polymerized actin in over half of the cells after 24 h. In contrast, macrophages infected with the spvB or SPI2 (ssaV or ssaJ) mutant strain retained normal F-actin filaments, despite similar numbers of intracellular bacteria. We conclude that SpvB and a functional SPI2 TTSS are essential for Salmonella-induced delayed cytotoxicity of human macrophages.
authors.affiliation: Department of Medicine, School of Medicine, University of California at San Diego, La Jolla 92093-0640, USA.
authors.forename: Sara H
authors.initials: SH
authors.lastname: Browne
authors.forename: Marc L
authors.initials: ML
authors.lastname: Lesnick
authors.forename: Donald G
authors.initials: DG
authors.lastname: Guiney
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D015169:Colony Count, Microbial; D006801:Humans; D008264:Macrophages / Q000382:microbiology* / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D009000:Monocytes / Q000382:microbiology* / Q000502:physiology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019779:Salmonella enterica / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D012486:Salmonella typhimurium / Q000145:classification / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C440638:SPI-2 protein, Salmonella; D037521:Virulence Factors; D036002:ADP Ribose Transferases; C415223:spvB protein, Salmonella enterica virulence plasmid; D011065:Poly(ADP-ribose) Polymerases