Negative selection

Definition

Negative selection is the process by which T lymphocytes (T cells) that react strongly with self-antigens are eliminated in the thymus to prevent autoimmune responses. This ensures that only T cells tolerant to self-antigens mature and enter the peripheral immune system.

5 Must Know Facts For Your Next Test

1. Negative selection occurs in the thymus during T cell development.
2. It involves the apoptosis of T cells that bind too strongly to self-antigens presented by thymic epithelial cells.
3. This process helps maintain self-tolerance and prevent autoimmune diseases.
4. Negative selection is crucial for central tolerance, a key component of immune system regulation.
5. Approximately 95% of developing T cells undergo apoptosis due to negative selection.

Review Questions

• Where does negative selection of T cells occur?
• Why is negative selection important for preventing autoimmune responses?
• What happens to T cells that react strongly with self-antigens during negative selection?

Related terms

Positive Selection: Process in the thymus where T cells with receptors capable of recognizing MHC molecules are allowed to survive.

Central Tolerance:

Mechanism occurring in primary lymphoid organs (thymus for T cells, bone marrow for B cells) aimed at eliminating self-reactive lymphocytes.

Self-Antigen: Any molecule or chemical group produced by an organism's own body that can induce an immune response.