Phagocytosis of opsonized apoptotic cells: roles for 'old-fashioned' receptors for antibody and complement

Clin Exp Immunol. 2004 Feb;135(2):181-5. doi: 10.1111/j.1365-2249.2003.02330.x.

Abstract

Efficient phagocytic clearance of apoptotic cells is crucial in many biological processes. A bewildering array of phagocyte receptors have been implicated in apoptotic cell clearance, but there is little convincing evidence that they act directly as apoptotic cell receptors. Alternatively, apoptotic cells may become opsonized, whereby naturally occurring soluble factors (opsonins) bind to the cell surface and initiate phagocytosis. Evidence is accumulating that antibodies and complement proteins opsonize apoptotic cells, leading to phagocytosis mediated by well-defined 'old-fashioned' receptors for immunoglobulin-Fc and complement. In this review we summarize the evidence that opsonization is necessary for high capacity clearance of apoptotic cells, which would render putative direct apoptotic cell receptors redundant.

Publication types

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

MeSH terms

  • Acute-Phase Proteins / immunology
  • Antibodies / immunology*
  • Anticoagulants / immunology
  • Apoptosis / immunology*
  • Collectins / immunology
  • Complement System Proteins / immunology*
  • Humans
  • Immunoglobulin Fc Fragments / immunology
  • Immunoglobulin G / immunology
  • Opsonin Proteins / immunology
  • Phagocytosis / immunology*
  • Receptors, Complement / immunology
  • Receptors, Immunologic / immunology*
  • Serum / immunology

Substances

  • Acute-Phase Proteins
  • Antibodies
  • Anticoagulants
  • Collectins
  • Immunoglobulin Fc Fragments
  • Immunoglobulin G
  • Opsonin Proteins
  • Receptors, Complement
  • Receptors, Immunologic
  • Complement System Proteins