title: SPI-1 encoded genes of Salmonella Typhimurium influence differential polarization of porcine alveolar macrophages in vitro.
abstract: BACKGROUND
  Within the last decade, macrophages have been shown to be capable of differentiating toward a classically activated phenotype (M1) with a high antimicrobial potential or an alternatively activated phenotype (M2). Some pathogens are capable of interfering with differentiation in order to down-regulate the anti-microbial activity and enhance their survival in the host.
  
  
  RESULTS
  To test this ability in Salmonella enterica serovar Typhimurium, we infected porcine alveolar macrophages with wild-type Salmonella Typhimurium and its isogenic mutants devoid of two major pathogenicity islands, SPI-1 and SPI-2. The induction of genes linked with M1 or M2 polarization was determined by quantification of gene expression by RT-qPCR. The ΔSPI-1 mutant induced a high, dose-dependent M1 response but a low M2 response in infected macrophages. On the other hand, wild-type Salmonella Typhimurium induced a low M1 response but a high, dose-dependent M2 response in infected macrophages. The response to ΔSPI-2 mutant infection was virtually the same as the wild-type strain.
  
  
  CONCLUSIONS
  We therefore propose that Salmonella Typhimurium DT104 studied here can polarize macrophages towards the less bactericidal M2 phenotype and that this polarization is dependent on the type III secretion system encoded by SPI-1.
authors: Veterinary Research Institute, Hudcova Brno, Czech Republic.
authors: Kamila
authors: K
authors: Kyrova
authors: Hana
authors: H
authors: Stepanova
authors: Ivan
authors: I
authors: Rychlik
authors: Martin
authors: M
authors: Faldyna
authors: Jiri
authors: J
authors: Volf
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D016676:Macrophages, Alveolar / Q000166:cytology* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013552:Swine; D059467:Transcriptome
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; C419942:Spi1 protein, Salmonella