REVIEW article
Front. Microbiol.
Sec. Food Microbiology
This article is part of the Research TopicProbiotic Potential: Lactic Acid Bacteria in Advancing Functional Foods and Health OutcomesView all 13 articles
Overview of the immunomodulatory role of bacterial probiotic-derived peptidoglycan: From molecular insights to therapeutic application
Provisionally accepted
Omer Qutaiba B. Allela1*
Abdulkareem Shareef2Hayder Naji Sameer3Ahmed Yaseen4Zainab H. Athab5Mohaned Adil6- 1Department of Pharmacy, AlNoor University College, Nineveh, Iraq
- 2Ahl Al Bayt University, Karbala, Iraq
- 3University of Thi-Qar, Nasiriyah, Iraq
- 4Gilgamesh University, Baghdad, Iraq
- 5Al-Zahrawi University College, Karbala, Iraq
- 6Al-Farahidi University, Baghdad, Iraq
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Probiotics are well recognized for their ability to modulate host immune responses; however, growing evidence indicates that many of their beneficial effects are mediated by structural components rather than by viable microorganisms. Among these components, probiotic-derived peptidoglycan has emerged as a key immunologically active molecule with a critical role in regulating both innate and adaptive immunity. Although substantial experimental data exist regarding its underlying mechanisms, the context-dependent immunomodulatory and anti-inflammatory functions of peptidoglycan have not been comprehensively integrated. In this review, we provide an up-to-date and comprehensive overview of the molecular and cellular mechanisms that govern the immunoregulatory properties of probiotic-derived peptidoglycan. We first discuss the structural diversity and processing of peptidoglycan and their implications for host recognition via pattern-recognition receptors, particularly Toll-like receptor 2 (TLR2) and nucleotide-binding oligomerization domain proteins 1 and 2 (NOD1/2). We then critically evaluate current evidence supporting the therapeutic potential of probiotic-derived peptidoglycan in infectious diseases, inflammatory bowel disease (IBD), autoimmune disorders, allergic inflammation, and cancer. Collectively, these findings suggest that peptidoglycan holds considerable promise for the development of next-generation microbiota-based immunotherapeutic strategies.
Keywords: Cancer, Immune Modulation, Infection, Inflammation, Inflammatory bowel disease (IBD), Nucleotide-binding oligomerization domain (NOD) receptor, Probiotic-derived peptidoglycan, Toll-like receptor (TLR)
Received: 06 Dec 2025; Accepted: 02 Jan 2026.
Copyright: © 2026 Qutaiba B. Allela, Shareef, Naji Sameer, Yaseen, H. Athab and Adil. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Omer Qutaiba B. Allela
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