Structure of the CAMPATH-1 antigen, a glycosylphosphatidylinositol-anchored glycoprotein which is an exceptionally good target for complement lysis.
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Xia MQ, Hale G, Lifely MR, Ferguson MA, Campbell D, Packman L, Waldmann H
Structure of the CAMPATH-1 antigen, a glycosylphosphatidylinositol-anchored glycoprotein which is an exceptionally good target for complement lysis.
Biochem J. 1993 Aug 1;293 ( Pt 3):633-40.
- PubMed ID
- 7688956 [ View in PubMed]
- Abstract
CAMPATH-1 antibodies recognize a unique molecule on human lymphocytes and are unusually efficient at causing cell lysis with homologous complement. They have been successfully used for lymphocyte depletion in vivo in a variety of diseases. We find that the antigen is a very small glycosylphosphatidylinositol (GPI)-anchored glycoprotein with a mature peptide comprising only 12 amino acids. It can be separated into two distinct antigenic fractions which differ in their susceptibility to phosphatidylinositol-specific phospholipase C. There is one N-linked glycosylation site, but no evidence for O-glycosylation despite the presence of several serine and threonine residues. The antibodies were found to bind, albeit with a generally reduced affinity, to a proteolytic fragment containing the C-terminal tripeptide and the GPI anchor. We postulate that one of the reasons why the CAMPATH-1 antibodies are so good for cell lysis is because they bind to an epitope which is likely to be very close to the lipid bilayer.