Mechanisms in immune tolerance.

Self:nonself-discrimination is critical for the function of the immune system and survival of vertebrate species. The failure to respond to one's own antigens has been called self-tolerance. The mechanisms whereby such tolerance may be induced are reviewed herein. Emphasis is placed on the role of self-recognition involving suppressor T-cell pathways as well as on studies involving putative clonal deletion mechanisms. The important parameters for the induction of tolerance and the roles played by surface isotypes in discriminating immunogenic vs. tolerogenic signals will be emphasized. The possible involvement of multiple pathways for self or experimental tolerance is emphasized with the ultimate goal being the modulation of aberrant immune responses.