Structure-function study of the p55 subunit of murine IL-2 receptor by epitope mapping

J Immunol. 1991 Nov 1;147(9):2970-7.


Using a cell-free translation system we have expressed the Mr 55,000 subunit of the murine IL-2R (p55 IL-2R), which binds IL-2 with low affinity (Kd = 10 nM). Mutants and truncated forms of p55 IL-2R have been used to map the epitopes recognized by three anti-p55 IL-2R mAb: 135D5, 7D4, and 2E4. The mAb 135D5 inhibits IL-2 binding to p55 IL-2R and recognizes an epitope located between amino acids 64 to 125. This epitope can be mimicked by a synthetic peptide corresponding to the region defined by residues 72 to 88. However, the mAb 7D4 and 2E4 do not affect the IL-2 binding to p55 IL-2R. These mAb recognize an epitope of p55 IL-2R lying between residues 125 to 212 that can be mimicked with a peptide corresponding to amino acids 188 to 208. A strong correlation emerged between the experimental results on epitope mapping and predictions of potential antigenicity of murine p55 IL-2R. In addition, we described two internal initiation sites of p55 IL-2R mRNA under the in vitro conditions used leading to the production of significant amounts of N-terminal truncated p55 IL-2R proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / immunology
  • Base Sequence
  • Blotting, Western
  • DNA Mutational Analysis
  • Epitopes
  • Mice
  • Molecular Sequence Data
  • Oligonucleotides / chemistry
  • Peptides / chemistry
  • Peptides / immunology
  • Precipitin Tests
  • Receptors, Interleukin-2 / immunology*
  • Recombinant Proteins / immunology
  • Structure-Activity Relationship


  • Antibodies, Monoclonal
  • Epitopes
  • Oligonucleotides
  • Peptides
  • Receptors, Interleukin-2
  • Recombinant Proteins