15 June 1990
Vol 248, Issue 4961

About The Cover

An allegory of immune tolerance, inspired by M. C. Escher. Immune function depends on distinguishing between self and nonself. When the immune system cannot determine whether an antigen is self or foreign, self tolerance may break down and autoimmune disease ensues. The articles on tolerance in the immune system begin on page 1335. [Concept by Linda J. Miller, illustration by Julie Cherry]