title: Degeneracy, mimicry and crossreactivity in immune recognition.
abstract: 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.
authors.affiliation: Conceptual Immunology Group, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA. cohn@salk.edu
authors.forename: Melvin
authors.initials: M
authors.lastname: Cohn
mesh_terms: D000818:Animals; D001324:Autoantigens; D001666:Binding Sites, Antibody; D003429:Cross Reactions; D000939:Epitopes; D006801:Humans; D007109:Immunity; D018448:Models, Immunological; D018716:Molecular Mimicry; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism
chemical_list: D001324:Autoantigens; D000939:Epitopes; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell