`t-cells Are Mhc Restricted`. Discuss This Statement.

`T- stalls be MHC restrictedT- carrels , which belong to a group of white farm animal of products cells known as lymphocytes , play a decisive federal agency in cell mediated immunity . They differ from inverse lymphocyte types , such(prenominal) as B-cells and Natural Killer NK cells by the charge of the T-cell receptor (TCR . T cells argon called as such because their maturement primarily is in the thymusT-cells argon divided into 2 major groups . T-helper CD4 cells , the middlemen of the HYPERLINK hypertext carry-over protocol /en .wikipedia .org /wiki / reconciling_ immune_sy foot \o Adaptive immune sy home adaptive immune system , unfreeze HYPERLINK hypertext transfer protocol /en .wikipedia .org /wiki /Cytokine \o Cytokine cytokines that holds a regulatory role in the immune response . T-cytotoxic cells CD 8 kill virally septic cells and tumor cells and ar also an important factor in transplant rejectionT-cells be further subdivided into Th1 and Th2 . The distinction mingled with CD4 and CD8 occurs during their development in the thymus . This occurs only after these cells have been activated during immune act in the peripheral lymphoid systemT-cells originate from haemopoietic stem cells in the bone marrow Hematopoietic precursors derived from hematopoietic stem cells populate the thymus and replicate to generate a all-embracing-grown population of immature thymocytes . Thymocytes are the T-cell precursors which develop and mature in the thymus (Schwarz B A , Bhandoola A . 2006 Double-positive thymocytes migrate into the thymic HYPERLINK hypertext transfer protocol /en .wikipedia .org /wiki /Cortex \o Cortex mantle where they are presented with host self-antigens complexed with Major Histocompatibility Complex HYPERLINK http /en .wikipedia .org /wiki /Major_histocomp atibility_complex \o Major histocompatibili! ty complex MHC molecules on the cortical epithelial scrawny . Only those thymocytes with affinity to the MHC complex receive a life-sustaining survival taper The remaining thymocytes analyse by caspase-mediated cell close also known as programmed cell death and their remains are phagocytosed by macrophages . This process is called positive lap up .

Double-positive cells that are positively selected on corresponding MHC class II molecules pose CD4 cells , and cells positively selected on matching MHC class I molecules get under ones skin CD8 cellsThymocytes that survive positive survival migrate towa rds the area between the thymic cortex and thymic HYPERLINK http /en .wikipedia .org /wiki / candent lamp \o Medulla incandescent lamp . While in the medulla , they are once more presented with self-antigen complexed with Major Histocompatibility Complex MHC molecules on HYPERLINK http /en .wikipedia .org /wiki /Antigen_presenting_cell \o Antigen presenting cell antigen-presenting cells APCs such as HYPERLINK http /en .wikipedia .org /wiki /D endingritic_cell \o Dendritic cell dendritic cells and HYPERLINK http /en .wikipedia .org /wiki /Macrophage \o Macrophage macrophages HYPERLINK http /en .wikipedia .org /wiki /Thymocytes \o Thymocytes Thymocytes that react with the antigen receive an HYPERLINK http /en .wikipedia .org /wiki /Apoptosis \o Apoptosis apoptosis signal that causes their suicide . A majority of all thymocytes initially produced end die during thymic selection . A small minority of the survive cells are selected to become HYPERLINK http /en .wikiped ia .org /wiki / regulative_T_cell \o Regulatory T ce! ll regulatory T-cells . The remaining cells will past exit the thymus as napve T-cells . This process is called negative selection , an important mechanics of HYPERLINK http...If you want to get a full essay, order it on our website: OrderCustomPaper.com

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