THE SCIENCE of the Thymus

Central role in preventing autoimmunity

The thymus is the training ground of the immune system.

The thymus, located just above the heart, is where T cells learn to distinguish self from non-self. Within this organ, autoantigens representing nearly all peripheral proteins and tissues are presented to developing thymocytes in a process that leads to the elimination of autoreactive T cells and the generation of tolerogenic regulatory T cells (Tregs). Thymus-derived Tregs home to specific tissues where they exert broad anti-inflammatory effects and promote tissue repair.

Harnessing the natural process of central tolerance

1 Enter

Each immature thymocyte enters the thymus from the bone marrow and undergoes gene rearrangement to generate unique T cell receptors (TCRs), each of which is capable of recognizing and binding to any one of a billion different antigens.

2 Teach

Antigen-presenting cells (APCs) display self-antigens that engage TCRs on developing T cells. High-affinity recognition between a self-antigen and TCR promotes deletion of potentially autoreactive T cells. Medium (MED) affinity recognition promotes differentiation into tolerogenic Tregs that recognize and protect tissues bearing self-antigens.

3 home & tolerize

Mature thymic Tregs home to peripheral tissues that express their specific self-antigen, take up residence, and exert broad anti-inflammatory effects, promoting tolerance and preventing autoimmunity.