Lysozyme-modified probiotic components protect rats against polymicrobial sepsis: Role of macrophages and cathelicidin-related innate immunity

Heng Fu Bu, Xiao Wang, Ya Qin Zhu, Roxanne Y. Williams, Wei Hsueh, Xiaotian Zheng, Ranna A. Rozenfeld, Xiu Li Zuo, Xiao Di Tan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Severe sepsis is associated with dysfunction of the macrophage/monocyte, an important cellular effector of the innate immune system. Previous investigations suggested that probiotic components effectively enhance effector cell functions of the immune system in vivo. In this study, we produced bacteria-free, lysozyme-modified probiotic components (LzMPC) by treating the probiotic bacteria, Lactobacillus sp., with lysozyme. We showed that oral delivery of LzMPC effectively protected rats against lethality from polymicrobial sepsis induced by cecal ligation and puncture. We found that orally administrated LzMPC was engulfed by cells such as macrophages in the liver after crossing the intestinal barrier. Moreover, LzMPC-induccd protection was associated with an increase in bacterial clearance in the liver. In vitro, LzMPC up-regulated the expression of cathelicidin-related antimicrobial peptide (CRAMP) in macrophages and enhanced bactericidal activity of these cells. Furthermore, we demonstrated that surgical stress or cecal ligation and puncture caused a decrease in CRAMP expression in the liver, whereas enterai administration of LzMPC restored CRAMP gene expression in these animals. Using a neutralizing Ab, we showed that protection against sepsis by LzMPC treatment required endogenous CRAMP. In addition, macrophages from LzMPC-treated rats had an enhanced capacity of cytokine production in response to LPS or LzMPC stimulation. Together, our data suggest that the protective effect of LzMPC in sepsis is related to an enhanced cathelicidin-related innate immunity in macrophages. Therefore, LzMPC, a novel probiotic product, is a potent immunomodulator for macrophages and may be beneficial for the treatment of sepsis.

Original languageEnglish (US)
Pages (from-to)8767-8776
Number of pages10
JournalJournal of Immunology
Issue number12
StatePublished - Dec 15 2006

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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