Self and nonself: duality of immune system.
From the viewpoint of evolution, mammalian immunity has been developed to prevent invasion by foreign bodies including parasites and microorganisms and not to survey oncogenesis. The surveillance system on oncogenesis has been lost in the evolutionary process from amphibians to mammals. The essential duality between developmental antigens and tumor specific antigens is important in explaining what the target of self-defense mechanisms is. This duality between self-defense and defense against foreign bodies originated from invertebrates as shown in insects. Immunity has been developed to survey retrodifferentiation of somatic cells and to drive the developmental process in organogenesis. Under these conditions, the clonal deletion theory of immunocyte differentiation will lose its teleological meaning. Also, the hypothesis explaining self reactivity of immunity by the immune system recognizing only an 'internal image' composed of an idio-antiidio network of immunocytes and antibodies is overly pedantic.
Department of Orthopedic Surgery, Gunma University School of Medicine, Japan.
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Chigira
D000818:Animals; D000951:Antigens, Neoplasm; D015551:Autoimmunity; D005075:Biological Evolution; D006801:Humans; D007107:Immune System / Q000502:physiology*; D008954:Models, Biological; D009369:Neoplasms / Q000276:immunology
D000951:Antigens, Neoplasm