MARCO, an innate activation marker of macrophages, is a class A scavenger receptor for Neisseria meningitidis

Eur J Immunol. 2006 Apr;36(4):940-9. doi: 10.1002/eji.200535389.

Abstract

The scavenger receptor-A I/II (SR-A) and macrophage receptor with collagenous domain (MARCO) share a common domain organisation and ligand repertoire, including selected polyanions and gram-positive and -negative organisms, but differ in fine specificity of ligand binding, tissue distribution and regulation. Neisseria meningitidis (NM) is a selective ligand for SR-A, but there is evidence for an additional SR-A-independent, polyanion-sensitive component for NM recognition. We therefore studied the relative contribution of MARCO and SR-A to binding of NM by resident and elicited peritoneal macrophages obtained from MARCO-/-, SR-A-/- and SR-A-MARCO-/- mice. Results confirmed that both mouse and human MARCO are able to bind NM independently of NM LPS. MARCO and SR-A contributed independently to NM binding, correlating with their expression levels in different cell populations, but neither of these two molecules was required for release of TNF-alpha and nitric oxide. We propose that the TLR-dependent induction of MARCO by innate immune stimulation enhances recognition and uptake of pathogenic organisms such as NM, thus contributing to host defence against infection.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers
  • Flow Cytometry
  • Humans
  • Macrophage Activation / immunology*
  • Macrophages / immunology*
  • Macrophages / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Neisseria meningitidis / immunology*
  • Receptors, Immunologic / immunology*
  • Receptors, Immunologic / metabolism
  • Scavenger Receptors, Class A / immunology*
  • Scavenger Receptors, Class A / metabolism
  • Transfection

Substances

  • Biomarkers
  • MARCO protein, human
  • MSR1 protein, human
  • Receptors, Immunologic
  • Scavenger Receptors, Class A