Tolerance and paralysis

Abstract

As soon as immunologists began to use red blood cells or blood serum as experimental antigens it was recognized that an animal which could react strongly against red cells from another species gave no response against an injection of its own cells or in general against cells from another individual of the same species. On the simplest common-sense grounds, too, it was obvious that there must be some inbuilt inhibition preventing immune reactions against the body’s own constituents. Ehrlich spoke of ‘horror autotoxicus’ as a general principle to cover this immunological distinction between self and not self. In discussing auto-immune disease we shall be concerned almost wholly with conditions where to some extent these normal inhibitions have broken down. The fact that auto-immune disease is rare in man and exceptionally rare in other animals merely underlines the importance of the inviolability of self-components.