Probiotics: Microbial Experts in Immunomodulation of Mucosal Macrophage-Driven Responses

Editorial. Probiotics are live microbes conferring health benefit to the host, by reinforcing mucosal barrier integrity and functionality. Recently, attention has focussed on their immunomodulatory role: a microbial on-oوٴ switch mediating homeostatic/tolerogenic mucosal responses, whilst maintaining responsiveness to pathogenic infection [1]. As with pathogenic bacteria and their conserved pathogen associated molecular patterns (PAMPs), probiotics exhibit microbial associated molecular patterns (MAMPs), thus pattern recognition is fundamental to understanding how probiotics modulate immune fate decisions: activation or tolerisation. Probiotic MAMPs, include LTA, PGN, LPS, flaJellLn and CpG DNA; initiating Lnflammatory responses through recognition by pattern recognition receptors, TLR2, NOD1/NOD2, TLR4, TLR5, TLR9, respectively. PRR recognition of both pathogen and probiotic MAMPs highlights our limited understanding of pattern recognition definLnJ protective anti-pathogen responses or immunomodulatory responses to beneficLal microbes.