The immune system evolved to discriminate infectious nonself from noninfectious self

Immunol Today. 1992 Jan;13(1):11-6. doi: 10.1016/0167-5699(92)90198-G.


Here, Charles Janeway argues that the requirement for two signals to initiate the adaptive immune response may reflect the evolutionary history of host defences. Early phases of host defence involve receptors and ligands that may have controlled immune responses prior to the development of clonally-distributed receptors encoded in rearranging genes. The former receptors persist in contemporary vertebrates both to trigger innate or nonclonal responses and to signal to lymphocytes that a particular antigen is associated with a microorganism.

Publication types

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

MeSH terms

  • Animals
  • Biological Evolution
  • Humans
  • Immune System / physiology*
  • Infections / immunology*
  • Receptors, Immunologic / genetics


  • Receptors, Immunologic