On the mystique of the immunological self.

Since the time of Paul Ehrlich 100 years ago, we have known that the immunological apparatus somehow inhibits most damaging autoimmune responses while permitting a response to exogenous immunogens. With the discovery of tolerance, the concept of immunological surveillance, and especially with the discovery of HLA restriction of T-cell recognition, the term "the immunological self" and the phrase "self-nonself discrimination" have gained wide currency. Immunology has been called "The Science of Self", and self-nonself discrimination has been assigned as the driving force for its complex evolution. The concept of self has thus been given such mystical trappings since the time of Macfarlane Burnet that recent workers have felt free to pronounce it the central paradigm of modern immunology, and to claim to overthrow it! In this article, we challenge some of the more egregious claims about the immunological self by recalling important historical findings, by reviewing the mechanisms of Darwinian evolution, and by remembering that the general pathology of immunogenic inflammation shows that the immune response cannot discriminate between the benign and the noxious.