BASIC RESEARCH
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 28, 2005; 11(40): 6330-6337
Published online Oct 28, 2005. doi: 10.3748/wjg.v11.i40.6330
Distinct immune response induced by peptidoglycan derived from Lactobacillus sp
Jin Sun, Yong-Hui Shi, Guo-Wei Le, Xi-Yi Ma
Yong-Hui Shi, Guo-Wei Le, the Key Laboratory of Food Science and Security, Ministry of Education, Southern Yangtze University, Wuxi 214036, Jiangsu Province, China
Jin Sun, Yong-Hui Shi, Guo-Wei Le, Xi-Yi Ma, Institute of Food Nutrition and Safety, School of Food Science and Technology, Southern Yangtze University, Wuxi 214036, Jiangsu Province, China
Author contributions: All authors contributed equally to the work.
Supported by the PhD Programs Foundation of Ministry of Education of China, No. 20040295005
Correspondence to: Professor Yong-Hui Shi, Institute of Food Nutrition and Safety, School of Food Science and Technology, Southern Yangtze University, 170 Huihe Road, Wuxi 214036, Jiangsu Province, China. yhshi@sytu.edu.cn
Telephone: +86-510-5869236 Fax: +86-510-5869236
Received: November 28, 2004
Revised: January 1, 2005
Accepted: January 3, 2005
Published online: October 28, 2005
Abstract

AIM: 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-κB 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.

CONCLUSION: 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.

Keywords: Lactobacillus peptidoglycan; Gene expression; Immune response