Which plays a role in central tolerance for T cell selection?
Table of Contents
THYMIC APCs: DENDRITIC CELLS Both medullary and cortical DCs are potentially important in central tolerance by inducing the apoptosis of self-reactive thymocytes.
What is central tolerance mechanism?
Central tolerance refers to the regulatory mechanisms that occur at the early stages of B cell development in the bone marrow, when B cells carry a surface antigen receptor of the IgM class but are not fully mature.
What is central vs peripheral tolerance?
Central tolerance is a state of immune tolerance that is induced originally in the thymus and bone marrow. Whereas, peripheral tolerance is a state of immune tolerance that is induced originally in the lymph nodes and other tissues.
Where do T cells become immunologically tolerant?
Central tolerance mechanisms occur during lymphocyte development, either in the thymus for T cells or in the bone marrow for B cells.
What does T cell tolerance mean?
T cell-mediated immune tolerance is a state of unresponsiveness of T cells towards specific self or non-self antigens.
What is the role of AIRE protein in central tolerance?
Studies on the role of AIRE in the central immune system have demonstrated that AIRE can eliminate autoreactive T cells by regulating the expression of a series of tissue specific antigens promiscuously in medullary thymic epithelial cells (mTECs) and induce regulatory T cell (Treg) production to maintain central …
What is meant by T cell tolerance?
What is central tolerance B cells?
How is tolerance maintained?
Regulatory immune cells circulate throughout the body to maintain tolerance. Besides limiting autoreactive cells, regulatory cells are important for turning an immune response off after the problem is resolved.
Why is peripheral tolerance important?
It takes place in the immune periphery (after T and B cells egress from primary lymphoid organs). Its main purpose is to ensure that self-reactive T and B cells which escaped central tolerance do not cause autoimmune disease. Peripheral tolerance prevents immune response to harmless food antigens and allergens, too.
Is AIRE central or peripheral tolerance?
The expression of Aire in the thymus is critical for both central tolerance by clonal deletion, and for peripheral tolerance via the generation of Tregs7. Interestingly, Aire expression can also be found in extrathymic Aire-expressing cells (eTACs) in peripheral lymphoid organs.
Where does central tolerance occur in T cells?
T cell central tolerance occurs in the thymus. T cells undergo positive and negative selection. T cell receptors must have the ability to recognize self major histocompatibility complex (MHC) molecules with bound non-self peptide. During positive selection, T cells are checked for their ability to bind peptide-MHC complexes with affinity.
What happens when T-cell tolerance fails?
Thus, failure of T-cell tolerance can lead to many different autoimmune diseases. The tolerance of T cells begins as soon as a T-cell receptor is formed and expressed on the cell surface of a T-cell progenitor in the thymus.
What is central tolerance?
Tolerance mechanisms that operate in the thymus before the maturation and circulation of T cells are referred to as “central tolerance.” However, not all antigens that T cells need to be tolerant of are expressed in the thymus, and thus central tolerance mechanisms alone are insufficient.
What is peripheral tolerance of T cells?
These mechanisms act on mature circulating T cells and are referred to as “peripheral tolerance.” CENTRAL TOLERANCE T lymphocytes arise from circulating bone-marrow-derived progenitors that home to the thymus.