Distinct immune response induced by peptidoglycan derived from Lactobacillus sp.
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.
Sun
Jin
J
Institute of Food Nutrition and Safety, School of Food Science and Technology, Southern Yangtze University, Wuxi 214036, Jiangsu Province, China.
Shi
Yong-Hui
YH
Le
Guo-Wei
GW
Ma
Xi-Yi
XY
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
D010457:Peptidoglycan