title: Distinct immune response induced by peptidoglycan derived from Lactobacillus sp.
abstract: OBJECTIVE
  To analyze the distinct immune responses induced by Lactobacillus peptidoglycan (PG).
  
  
  METHODS
  BALB/c mice were intraperitoneally injected with PG once a day for three consecutive days. Peritoneal macrophage and splenocyte mRNA was extracted and the gene expression profile was studied using high-density oligonucleotide microarrays. Inhibitory effects of Lactobacillus PG on colon tumor tissue were studied in vitro and in vivo.
  
  
  RESULTS
  The gene expression profiles revealed that the TLR-NF-kappaB; and Jak-STAT signaling pathways were highly activated. An inflammatory phenotype was induced when peritoneal macrophages were initially exposed to Lactobacillus PG and switched to a more complex phenotype when BALB/c mice were treated with three doses of Lactobacillus PG. A protective physiological inflammatory response was induced after three consecutive days of PG treatment. It was tending toward Th1 dominant immune response. Lactobacillus PG also appeared to induce a significant in vivo anti-colon tumor effect.
  
  
  CONCLUSIONS
  Lactobacillus PG is responsible for certain immune responses induced by Lactobacilli. Anti-tumor effects of Lactobacilli are likely to attribute to the activation of macrophages by PG expressed on the bacterial cell surface.
authors.affiliation: Institute of Food Nutrition and Safety, School of Food Science and Technology, Southern Yangtze University, Wuxi 214036, Jiangsu Province, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Sun
authors.forename: Yong-Hui
authors.initials: YH
authors.lastname: Shi
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Le
authors.forename: Xi-Yi
authors.initials: XY
authors.lastname: Ma
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D007107:Immune System / Q000502:physiology*; D007249:Inflammation / Q000276:immunology; D007778:Lactobacillus / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D010457:Peptidoglycan / Q000276:immunology*; D010641:Phenotype; D015398:Signal Transduction / Q000502:physiology; D013154:Spleen / Q000166:cytology / Q000276:immunology
chemical_list: D010457:Peptidoglycan