Anergy (immunology)

In immunology, anergy is the lack of reaction to an antigen by switching off the immune response . Anergy is one of the mechanisms by which the immune system prevents T cells from attacking the body's own tissues . Anergy is a permanent property. An anergic T cell is not reactivated under normal conditions. In some systems, however, interleukin-2 can reactivate an anergic cell.

During the maturation of T cells in the thymus , many so-called autoreactive cells are normally formed. These are cells that do not recognize the body's own antigens as such and would therefore attack the body's own tissue. Most of these cells are killed in the thymus, but a few autoreactive T cells reach the body periphery. If a T cell, regardless of whether it is autoreactive or not, now recognizes an antigen in the periphery, its activation is also dependent on the presence of costimulatory molecules such as B7-1 or B7-2. If the T cell does not receive any co-stimulatory signals when an antigen is detected, it changes to the permanent state of anergy.

Pathogens that manage to weaken the immune response against themselves can thereby generate anergy. The immune system can be switched off selectively, and the pathogens are no longer attacked.