Figure 1.

A simplified paradigm illustrating where in the continuum of immune protection and homeostasis γδ T cells fall in relation to innate NK cells and the adaptive αβT cells. Innate NK and adaptive αβ T cells respond to the “missing self” and the “dangerous nonself,” respectively, while, between these two extremes, γδ T cells respond to the “safe nonself” and deal with the inevitable “distressed self.” These different “selves” and the immune response(s) that they trigger exist in a continuum and are modulated by the context in which they are presented. Besides, NK cells could contribute to responding to the “distressed self,” whereas αβ T cells have some regulatory training to temper the response to the “safe nonself” (cited from [10]).