Degeneracy, mimicry and crossreactivity in immune recognition

Mol Immunol. 2005 Mar;42(5):651-5. doi: 10.1016/j.molimm.2004.09.010.


Degeneracy of recognition of antigen by the immune system is being used as an argument that the self-nonself discrimination cannot be a property of the specificity of its antigen-receptors, TCR and BCR, but must rely on emergent properties derived from a set of complex interactions and pathways. This essay analyzes an alternative view by showing that degeneracy and specificity are not mutually exclusive properties. The self-nonself discrimination is the sole evolutionary selection pressure for the specificity of the TCR and BCR, which can be quantitated as a "Specificity Index." Degeneracy is a non-issue for the self-nonself discrimination largely because it is a problem of chemistry, not of biology.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Autoantigens
  • Binding Sites, Antibody
  • Cross Reactions
  • Epitopes
  • Humans
  • Immunity*
  • Models, Immunological
  • Molecular Mimicry
  • Receptors, Antigen, B-Cell / metabolism
  • Receptors, Antigen, T-Cell / metabolism


  • Autoantigens
  • Epitopes
  • Receptors, Antigen, B-Cell
  • Receptors, Antigen, T-Cell