Crosstalk Between Probiotics and Host Immunity: Antimicrobial Peptides‐Mediated Health Benefits

The intricate crosstalk between probiotics and the host immune system is increasingly recognized as a central determinant of mucosal integrity, resistance to infection, and systemic homeostasis. This narrative review synthesizes current evidence identified through comprehensive searches of major scientific databases, including PubMed, Scopus, and Web of Science, using targeted keywords related to probiotics, antimicrobial peptides (AMPs), and immune modulation. Emerging evidence indicates that, beyond their traditional metabolic roles, probiotics exert significant immunomodulatory effects through the induction and regulation of AMPs, including bacteriocins, defensins, lysozymes, and cathelicidins. Mechanistically, probiotics activate key host signaling pathways, stimulating epithelial and immune cells to enhance AMP expression. These peptides exhibit broad-spectrum antimicrobial activity by disrupting microbial membranes, inhibiting quorum sensing, and excluding pathogens, thereby strengthening mucosal barrier function and maintaining microbial homeostasis. Additionally, host immune signaling further promotes probiotic colonization and AMPs biosynthesis, establishing a tightly regulated bidirectional feedback mechanism. This review aims to highlight the current evidence on the bidirectional crosstalk between probiotics and host immunity, with particular emphasis on AMPs-mediated mechanisms underlying mucosal protection, immune modulation, and pathogen resistance.