Birth of the Cellular Guardians: T-cell Development
Autoimmunity
The major histocompatibility complex (MHC) is encoded by a single locus on human chromosome 6. Self-reactive T-cells which recognize host MHC molecules must be eliminated in the thymus by a process called negative selection. Self-reactive T-cells which escape thymic negative selection populate the periphery.
The main role of MHC class I is to present peptide antigens to CD8+ cytotoxic T lymphocytes.
Thymic Escape
Thymic escape defines the situation where self-reactive single positive mature T-cells escape the process of negative selection in the thymus. A competing theory for generation of self-reactive T-cells is that the antigenic repitoire in the thymus differs from that of the periphery, and that autoreactive T-cells simply encounter a host-antigen for the first time outside of the thymus. The former hypothesis is the basis for studying TCR-pMHC (T-cell receptor-peptide majorhistocompatibility complex) interactions, and the divergent responses of such interactions which range from tolerance to immunity.
The major histocompatibility complex (MHC) is encoded by a single locus on human chromosome 6. Self-reactive T-cells which recognize host MHC molecules must be eliminated in the thymus by a process called negative selection. Self-reactive T-cells which escape thymic negative selection populate the periphery.
The main role of MHC class I is to present peptide antigens to CD8+ cytotoxic T lymphocytes.
Thymic Escape
Thymic escape defines the situation where self-reactive single positive mature T-cells escape the process of negative selection in the thymus. A competing theory for generation of self-reactive T-cells is that the antigenic repitoire in the thymus differs from that of the periphery, and that autoreactive T-cells simply encounter a host-antigen for the first time outside of the thymus. The former hypothesis is the basis for studying TCR-pMHC (T-cell receptor-peptide majorhistocompatibility complex) interactions, and the divergent responses of such interactions which range from tolerance to immunity.