T cells

From The School of Biomedical Sciences Wiki
(Difference between revisions)
Jump to: navigation, search
(Created page with "T-cells or T-lymphocytes are a group of lymphocytes involved in specific immune response, specificlly antigen-specific cellular interactions. There are two main subsets; Cytotoxi...")
 
 
(8 intermediate revisions by 6 users not shown)
Line 1: Line 1:
T-cells or T-lymphocytes are a group of lymphocytes involved in specific immune response, specificlly antigen-specific cellular interactions. There are two main subsets; Cytotoxic T-cells and Helper T-cells, Helper T-cells are further divided into inflammatory (TH1 )and (TH2 ) Helper cells which asssist B-cells by forming antibodies. T-cells are formed from bone marrow stem cells that undergo maturation in the Thymus;<ref name="Brock Biology of Microorganisms">Michael Madigan, John Martinko, David Stahl, David Clark. (2012) Brock Biology of Microorganisms, Thirteenth Edition, San Francisco: Pearson. 246-249.</ref>.  
+
T-cells or T-lymphocytes are a group of [[Lymphocytes|lymphocytes]] involved in specific immune response, specifically antigen-specific cellular interactions. There are two main subsets; [[Cytotoxic T-cells|Cytotoxic T-cells]] and [[Helper T-cells|Helper T-cells]], Helper T-cells are further divided into inflammatory ([[TH1|TH1]]) and ([[TH2|TH2]]) Helper cells which assist [[B-cells|B-cells]] by forming [[Antibody|antibodies]]. Cytotoxic T-cells are also known as CD8+ T cells, and Helper T-cells are also known as CD4+ T cells. T-cells are formed from bone marrow stem cells that undergo maturation in the [[Thymus|Thymus]]<ref>Michael Madigan, John Martinko, David Stahl, David Clark. (2012) Brock Biology of Microorganisms, Thirteenth Edition, San Francisco: Pearson. 246-249</ref>.  
  
<br>  
+
Individual T cells are able to recognise only certain antigens, discriminating between antigens using protein molecules on the cell surface called receptors. The receptor and the antigen fit together like a lock and a key only when their shapes match perfectly. The number and specificity of T cell receptors appear to be determined by the cell’s genes<ref>http://www.nationalmssociety.org/What-is-MS/Definition-of-MS/T-cells</ref>.
  
=== References&nbsp;  ===
+
Before T cells have encountered an antigen, they are known as naive T cells and they have a low affinity for Interleukin-2 (IL-2). Naive T cells enter the [[Lymph_node|lymph node]] from blood via high endothelial venules (HEV), to move to a T cell area rich in [[Dendritic_cells|dendritic cells]] and [[Macrophages|macrophages]] ([[Antigen_presenting_cells|APC]]). [[Antigen_presenting_cells|APC]] present specific antigens to the T cell, and deliver other activation signals (e.g [[Cytokines|cytokines]]). Once they recognise an antigen they become activated and once activated they have a high affinity for IL-2 which leads to lots of IL-2 binding which causes a proliferation of T cells (binding of IL-2 causes T cells to begin the cell cycle)<ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267244/</ref>. T cells which are not activated (i.e. they did not encounter any [[Antigen|antigen]] or [[MHC_Molecules|MHC]]), leave the lymph node via cortical sinuses into the lymphatics to re-enter cirulation.
  
&lt;references/&gt;
+
Activation of T cells by antigen recognition also causes them to differentiate into 3 different types of T cells. CD8 T cells differentiate into Cytotoxic T cells and CD4 T Cells differentiate into CD4 TH1 and CD4 TH2 cells<ref name="Janeway's Immunology 5th edition">https://www.ncbi.nlm.nih.gov/books/NBK10762/</ref>.
 +
 
 +
CD4+ T cells recognise peptides bound to MHC class II complexes bound on the cell surface, whereas CD8+ T cells recognise peptides bound to MHC class I complexes bound to the cell surface.
 +
 
 +
=== Referneces  ===
 +
 
 +
<references />

Latest revision as of 13:39, 18 October 2018

T-cells or T-lymphocytes are a group of lymphocytes involved in specific immune response, specifically antigen-specific cellular interactions. There are two main subsets; Cytotoxic T-cells and Helper T-cells, Helper T-cells are further divided into inflammatory (TH1) and (TH2) Helper cells which assist B-cells by forming antibodies. Cytotoxic T-cells are also known as CD8+ T cells, and Helper T-cells are also known as CD4+ T cells. T-cells are formed from bone marrow stem cells that undergo maturation in the Thymus[1].

Individual T cells are able to recognise only certain antigens, discriminating between antigens using protein molecules on the cell surface called receptors. The receptor and the antigen fit together like a lock and a key only when their shapes match perfectly. The number and specificity of T cell receptors appear to be determined by the cell’s genes[2].

Before T cells have encountered an antigen, they are known as naive T cells and they have a low affinity for Interleukin-2 (IL-2). Naive T cells enter the lymph node from blood via high endothelial venules (HEV), to move to a T cell area rich in dendritic cells and macrophages (APC). APC present specific antigens to the T cell, and deliver other activation signals (e.g cytokines). Once they recognise an antigen they become activated and once activated they have a high affinity for IL-2 which leads to lots of IL-2 binding which causes a proliferation of T cells (binding of IL-2 causes T cells to begin the cell cycle)[3]. T cells which are not activated (i.e. they did not encounter any antigen or MHC), leave the lymph node via cortical sinuses into the lymphatics to re-enter cirulation.

Activation of T cells by antigen recognition also causes them to differentiate into 3 different types of T cells. CD8 T cells differentiate into Cytotoxic T cells and CD4 T Cells differentiate into CD4 TH1 and CD4 TH2 cells[4].

CD4+ T cells recognise peptides bound to MHC class II complexes bound on the cell surface, whereas CD8+ T cells recognise peptides bound to MHC class I complexes bound to the cell surface.

Referneces

  1. Michael Madigan, John Martinko, David Stahl, David Clark. (2012) Brock Biology of Microorganisms, Thirteenth Edition, San Francisco: Pearson. 246-249
  2. http://www.nationalmssociety.org/What-is-MS/Definition-of-MS/T-cells
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267244/
  4. https://www.ncbi.nlm.nih.gov/books/NBK10762/
Personal tools
Namespaces
Variants
Actions
Navigation
Toolbox