Question

Steps to distinguish self vs non-self (negative selection - central tolerance)

Answer 1

The process of negative selection or central tolerance in T cell development involves eliminating self-reactive T cells in the thymus. T cells with functional T-cell receptors (TCR) move to the junction between the cortex and medulla, self-antigens are presented to the T cells, and T cells that bind strongly to the self-antigens undergo apoptosis.

Step-by-step explanation:

T-cell development involves a process known as negative selection or central tolerance. This process occurs in the thymus and helps distinguish self-reactive T cells from non-self-reactive T cells. Here are the steps of negative selection:

1. T cells that have developed functional T-cell receptors (TCR) in the cortex of the thymus move to the junction between the cortex and medulla where negative selection takes place.
2. Self-antigens, brought into the thymus by professional antigen-presenting cells, are presented to the T cells.
3. T cells that bind strongly to the self-antigens are selected for negative selection and are eliminated through apoptosis (programmed cell death).

By undergoing negative selection, only T cells that can bind to foreign antigens presented on major histocompatibility complex (MHC) molecules are allowed to mature and leave the thymus.

T cells with functional T-cell receptors (TCR) move to the junction between the cortex and medulla, self-antigens are presented to the T cells, and T cells that bind strongly to the self-antigens undergo apoptosis.