Anergy

A state of immune unresponsiveness.

Induced when the T cell's antigen receptor is stimulated, effectively freezing T cell responses pending a 'second signal' from the antigen-presenting cell.

The delivery of the second signal by the antigen-presenting cell rescues the activated T cell from anergy, allowing it to produce the lymphokines necessary for the growth of additional T cells.</P> T cells are small white blood cells that orchestrate and directly participate in the immune defenses.

Also known as T lymphocytes, they are processed in the thymus (which is why they are called T cells).