"Normal" elimination of aberrant autoimmune clones.

Tetraparental mouse chimaeras formed by aggregation of early embryos have been utilised in the study of immunological mechanisms. Tolerance in chimaeras has proven somewhat controversial, but recent evidence has suggested the existence of "classic" tolerance and furthermore that this is achieved by elimination of cells potentially capable of fatal self in equilibrium self reactivity. Clonal elimination was also considered to be responsible for the "correction" of the autoimmune disease of NZB mice made chimaeric with a normal strain. It is now suggested that a similar mechanism may be responsible for the "normal" elimination of any aberrant autoimmune clone in both mouse and man.