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Telling apart friend from foe: discriminating between commensals and pathogens at mucosal sites

Naren Srinivasan1

  • 1Sir William Dunn School of Pathology, University of Oxford, Oxford, UK. naren.srinivasan@path.ox.ac.uk

Innate Immunity
|January 20, 2010
PubMed

Insights

The mucosal immune system distinguishes between beneficial microbes and harmful pathogens. Recent findings explain how the gut maintains tolerance to commensals while responding to pathogens.

Area of Science:

  • Immunology
  • Microbiology
  • Gastroenterology

Background:

  • The human intestine hosts a dense microbial community, including commensals and pathogens.
  • Mucosal surfaces act as a barrier, employing innate immunity to detect microbes.
  • Discriminating between beneficial and harmful microbes is crucial for immune homeostasis.

Purpose of the Study:

  • To review current theories on how the mucosal immune system differentiates between commensals and pathogens.
  • To explain the mechanisms underlying immune tolerance to commensals.
  • To elucidate how inflammatory responses are mounted against pathogens.

Main Methods:

  • This review synthesizes recent discoveries and theoretical frameworks.
  • It examines the innate immune system's role in microbial recognition.
  • Focuses on signaling pathways involved in immune discrimination.

Main Results:

  • Innate immune recognition is microbial-specific and antigen-independent.
  • Mechanisms for distinguishing commensals from pathogens are increasingly understood.
  • The immune system balances tolerance and inflammation.

Conclusions:

  • The mucosal immune system employs sophisticated mechanisms to tolerate commensals.
  • It retains the capacity to initiate protective inflammatory responses against pathogens.
  • Understanding these mechanisms is key to gut health and disease.

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