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It is considered to be a stage of antigen presentation pathways. This process involves two distinct pathways for processing of antigens from an organism's own (self) proteins or intracellular pathogens (e.g. viruses ), or from phagocytosed pathogens (e.g. bacteria ); subsequent presentation of these antigens on class I or class II major ...
Antigen presentation stimulates immature T cells to become either mature "cytotoxic" CD8+ cells or mature "helper" CD4+ cells. An antigen-presenting cell (APC) or accessory cell is a cell that displays an antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation.
This antigen presentation pathway enables the immune system to detect transformed or infected cells displaying peptides from modified-self (mutated) or foreign proteins. [ 5 ] [ 6 ] In the presentation process, these proteins are mainly degraded into small peptides by cytosolic proteases in the proteasome , but there are also other cytoplasmic ...
It is in this way, the MHC class I-dependent pathway of antigen presentation, that the virus infected cells signal T-cells that abnormal proteins are being produced as a result of infection. The fate of the virus-infected cell is almost always induction of apoptosis through cell-mediated immunity, reducing the risk of infecting neighboring ...
Once the exogenous antigen peptide is loaded onto the MHC class I molecule, the complex is exported to the cell surface for antigen cross presentation. There is also evidence that suggest that cross-presentation requires a separate pathway in a proportion of CD8(+) dendritic cells that are able to cross-present.
Efficient presentation of antigenic peptides by MHC class I molecules provides the key signal for adaptive immune responses by cytotoxic (CD8 +) T lymphocytes.In the "endogenous" antigen presentation pathway, proteins synthesized by cells undergo cytosolic degradation and some of their peptide fragments are transported to the ER, where suitable-length peptides are loaded onto MHC class I ...
In humans, the MHC class II protein complex is encoded by the human leukocyte antigen gene complex (HLA). HLAs corresponding to MHC class II are HLA-DP, HLA-DM, HLA-DOA, HLA-DOB, HLA-DQ, and HLA-DR. Mutations in the HLA gene complex can lead to bare lymphocyte syndrome (BLS), which is a type of MHC class II deficiency.
The pathway involved in specific cases is dictated by intrinsic and extrinsic factors of allograft and directly influence nature and magnitude of T lymphocytes mediated immune response. Furthermore, variant tissues and organs such as skin or cornea or solid organ transplants can be recognized in different pathways and therefore are rejected in ...