Resolution of two overlapping neutralizing B cell epitopes within a solvent exposed, immunodominant α-helix in ricin toxin's enzymatic subunit

Toxicon. 2012 Oct;60(5):874-7. doi: 10.1016/j.toxicon.2012.06.014. Epub 2012 Jun 29.


Residues Y₉₁-T₁₁₆ of ricin toxin's enzymatic subunit (RTA) constitute an immunodominant loop-helix-loop motif that is the target of two potent toxin neutralizing monoclonal antibodies (mAbs), PB10 and R70. To define the exact epitope(s) recognized by these mAbs, we affinity enriched from a phage-displayed peptide library 12 mers that bound one or both of these mAbs. We report that PB10 recognizes a distinct but overlapping epitope with R70, in which residues Q₉₈, E₁₀₂, T₁₀₅, and H₁₀₆ are central to mAb recognition.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Antibodies, Monoclonal / metabolism
  • Catalytic Domain / genetics
  • Epitopes, B-Lymphocyte / genetics*
  • Epitopes, B-Lymphocyte / metabolism
  • Models, Molecular*
  • Molecular Sequence Data
  • Peptide Library
  • Protein Structure, Secondary / genetics*
  • Ricin / genetics*


  • Antibodies, Monoclonal
  • Epitopes, B-Lymphocyte
  • Peptide Library
  • Ricin