Table 1. Different theories of immunogenicity.

The self-nonself theory and the discontinuity theory of immunity predict the same outcomes for persistent or slowly changing endogenous (self) elements, and also for suddenly appearing and/or rapidly changing exogenous (nonself) elements. The theories make different predictions for rapidly changing endogenous elements, and for persistent or slowly changing exogenous elements.

Motifs	Examples	Self-nonself theory	Discontinuity theory
Rapidly changing endogenous elements	- Some significant bodily transformations, when uncontrolled (e.g., puberty, metamorphosis, pregnancy)	tolerogenic response	effector response
Persistent or slowly changing endogenous elements	- Usual functioning of the body	tolerogenic response	tolerogenic response
Persistent or slowly changing exogenous elements	- Many components of the microbiota acquired early during ontogeny - Chronic viruses	effector response	tolerogenic response
Suddenly appearing and/or rapidly changing exogenous elements	- Microorganisms that invade the organism suddenly - Most grafts	effector response	effector response