Any of various sites in the body where foreign tissue grafts do not induce immune responses. Such sites include the eye, brain, testis, and unborn fetus. So, for example, a corneal graft placed in the eye of an unrelated recipient will generally not be rejected by the recipient's immune system. Although antigens do migrate from these privileged sites, they either induce immunological tolerance or a nondestructive response. However, damage to such sites often results in autoimmune attack by the host immune system, as in multiple sclerosis.
Subjects: Biological Sciences.