Conformational changes in CD45 upon monoclonal antibody crosslinking

Hybridoma. 1996 Feb;15(1):11-6. doi: 10.1089/hyb.1996.15.11.


The CD45 protein tyrosine phosphatase is expressed in different isoforms that result from alternative splicing of three exons (A, B, and C) encoding regions near the N-terminus of the extracellular part of the molecule. We describe here a novel epitope on the N-terminal end of CD45 that is recognized by the MAb BL-TSub/2. Crossblocking studies showed that BL-TSub/2 and UCHL1 (CD45RO) binding sites are partially overlapping. However, in marked contrast to the CD45RO epitope, protease treatment of cells strongly diminished BL-TSub/2 binding. Similar to the UCHL1 epitope, the BL-TSub/2 binding site involves carbohydrate moieties, since neuraminidase treatment abrogated the reactivity of the MAb. Markedly, preincubation of cells with both CD45 common and CD45RA MAb induced a pronounced increase of BL-TSub/2 binding. This latter finding suggests that crosslinking of the CD45 molecule leads to conformational changes that could influence association of the molecule with putative ligands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal / pharmacology*
  • Binding Sites, Antibody
  • Cross-Linking Reagents
  • Humans
  • Leukocyte Common Antigens / chemistry*
  • Leukocyte Common Antigens / immunology
  • Mice
  • Mice, Inbred BALB C


  • Antibodies, Monoclonal
  • Cross-Linking Reagents
  • Leukocyte Common Antigens