Complement-mediated lysis by anti-CD20 mAb correlates with segregation into lipid rafts

Blood. 2003 Feb 1;101(3):1045-52. doi: 10.1182/blood-2002-06-1761. Epub 2002 Sep 19.


Despite the clinical success of anti-CD20 monoclonal antibody (mAb) in the treatment of lymphoma, there remains considerable uncertainty about its mechanism of action. Here we show that the ability of mAbs to translocate CD20 into low-density, detergent-insoluble membrane rafts appears to control how effectively they mediate complement lysis of lymphoma cells. In vitro studies using a panel of anti-B-cell mAbs revealed that the anti-CD20 mAbs, with one exception (B1), are unusually effective at recruiting human complement. Differences in complement recruitment could not be explained by the level of mAb binding or isotype but did correlate with the redistribution of CD20 in the cell membrane following mAb ligation. Membrane fractionation confirmed that B1, unlike 1F5 and rituximab, was unable to translocate CD20 into lipid rafts. In addition, we were able to drive B1 and a range of other anti-B-cell mAbs into a detergent-insoluble fraction of the cell by hyper-cross-linking with an F(ab')(2) anti-Ig Ab, a treatment that also conferred the ability to activate lytic complement. Thus, we have shown that an important mAb effector function appears to be controlled by movement of the target molecule into membrane rafts, either because a raft location favors complement activation by mAbs or because rafts are more sensitive to complement penetration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology*
  • Antibody Affinity
  • Antigens, CD20 / immunology*
  • Biological Transport
  • Cell Line
  • Complement System Proteins / immunology*
  • Complement System Proteins / metabolism
  • Cytotoxicity, Immunologic*
  • Humans
  • Membrane Microdomains / immunology*
  • Membrane Microdomains / metabolism
  • Octoxynol
  • Solubility


  • Antibodies, Monoclonal
  • Antigens, CD20
  • Octoxynol
  • Complement System Proteins