Generation and characterization of antibodies specific for caspase-cleaved neo-epitopes: a novel approach

Cell Death Dis. 2011 Sep 1;2(9):e205. doi: 10.1038/cddis.2011.91.

Abstract

Apoptosis research has been significantly aided by the generation of antibodies against caspase-cleaved peptide neo-epitopes. However, most of these antibodies recognize the N-terminal fragment and are specific for the protein in question. The aim of this project was to create antibodies, which could identify caspase-cleaved proteins without a priori knowledge of the cleavage sites or even the proteins themselves. We hypothesized that many caspase-cleavage products might have a common antigenic shape, given that they must all fit into the same active site of caspases. Rabbits were immunized with the eight most prevalent exposed C-terminal tetrapeptide sequences following caspase cleavage. After purification of the antibodies we demonstrated (1) their specificity for exposed C-terminal (but not internal) peptides, (2) their ability to detect known caspase-cleaved proteins from apoptotic cell lysates or supernatants from apoptotic cell culture and (3) their ability to detect a caspase-cleaved protein whose tetrapeptide sequence differs from the eight tetrapeptides used to generate the antibodies. These antibodies have the potential to identify novel neo-epitopes produced by caspase cleavage and so can be used to identify pathway-specific caspase cleavage events in a specific cell type. Additionally this methodology may be applied to generate antibodies against products of other proteases, which have a well-defined and non-promiscuous cleavage activity.

MeSH terms

  • Animals
  • Antibodies / chemistry
  • Antibodies / immunology
  • Antibodies / metabolism*
  • Apoptosis / drug effects
  • Caspases / immunology
  • Caspases / metabolism*
  • Cell Line, Tumor
  • Epitopes / immunology
  • Fluorouracil / toxicity
  • Humans
  • Immunoprecipitation
  • Oligopeptides / chemistry*
  • Oligopeptides / immunology
  • Rabbits

Substances

  • Antibodies
  • Epitopes
  • Oligopeptides
  • Caspases
  • Fluorouracil