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CRIg Functions as a Macrophage Pattern Recognition Receptor to Directly Bind and Capture Blood-Borne Gram-Positive

Zhutian Zeng1, Bas G J Surewaard2, Connie H Y Wong1

  • 1The Calvin, Phoebe & Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, Alberta, T2N 4N1, Canada.

Cell Host & Microbe
|June 28, 2016
PubMed

Insights

Kupffer cells capture Gram-positive bacteria via the complement receptor CRIg, which recognizes lipoteichoic acid. This direct interaction is crucial for preventing bacterial spread in the bloodstream.

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • Kupffer cells (KCs) are liver macrophages that clear blood-borne pathogens.
  • The mechanisms of KC pathogen capture are not fully understood.

Purpose of the Study:

  • To investigate the mechanisms by which Kupffer cells capture circulating Staphylococcus aureus.
  • To elucidate the role of the macrophage complement receptor CRIg in pathogen capture.

Main Methods:

  • Intra-vital imaging in mice infected with Staphylococcus aureus.
  • Assessment of bacterial capture dependence on complement and CRIg.
  • In vivo blocking of CRIg-lipoteichoic acid interaction.

Main Results:

  • Kupffer cells captured Staphylococcus aureus in a complement-independent manner, dependent on the macrophage complement receptor CRIg.
  • CRIg specifically recognized lipoteichoic acid (LTA) on Gram-positive bacteria.
  • Blocking CRIg-LTA interaction impaired bacterial capture and led to systemic dissemination.

Conclusions:

  • CRIg mediates direct capture of circulating Gram-positive bacteria by Kupffer cells.
  • CRIg acts as a pattern recognition receptor for LTA, crucial for innate immunity against Gram-positive bacteria.
Keywords:
Kupffer cellsStaphylococcus aureuscomplementintravital imagingliver

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