Working principles in the immune system implied by the "peptidic self" model.

The hypothesis that self as well as foreign proteins are processed into peptides and presented by major histocompatibility complex antigens leads to a set of working principles that could govern cellular interactions in immune responses. In particular, "idiopeptides," derived from immunoglobulins and T-cell receptors and recognized by appropriate T cells, are expected to play an important regulatory role. We show here that these speculations fit into a consistent view of the immune system.