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T cell differentiation (view source)
Revision as of 13:47, 9 September 2008
, 13:47, 9 September 2008→Antigen Presentation by Dendritic Cells
For any one cell the cytokine-secreting activation state is short-lived, lasting between 4 - 40 hours. After this time these cells either die, or mature into the long-lived memory cells. The proliferation of [[Lymphocytes - WikiBlood#T cells|T cells]] continues until antigen disappears.
For any one cell the cytokine-secreting activation state is short-lived, lasting between 4 - 40 hours. After this time these cells either die, or mature into the long-lived memory cells. The proliferation of [[Lymphocytes - WikiBlood#T cells|T cells]] continues until antigen disappears.
==Antigen Presentation by Dendritic Cells==
==Dendritic Cells==
[[Image:Lineages of dendritic cells.jpg|thumb|right|150px|Diagram showing the 2 Lineages of dendritic cells - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]
[[Image:Lineages of dendritic cells.jpg|thumb|right|150px|Diagram showing the 2 Lineages of dendritic cells - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]
*There are two different lineages of dendritic cells:
*There are two different lineages of dendritic cells:
**From myeloid precursor cells
**From myeloid precursor cells
*Produces [[Cytokines - WikiBlood#Chemokines|chemokines]]
*Produces [[Cytokines - WikiBlood#Chemokines|chemokines]]
===Maturation signals===
*Exogenous
*Exogenous
**Bacteria or their products (LPS, LTA, lipoproteins)
**Bacteria or their products (LPS, LTA, lipoproteins)
**Inflammatory mediators (IL-1/TNF-a, hsp, FcR)
**Inflammatory mediators (IL-1/TNF-a, hsp, FcR)
**Immune cells (CD40L, CD47, FasL)
**Immune cells (CD40L, CD47, FasL)
[[Image:Maturation of Dendritic Cells.jpg|thumb|right|150px|Maturation of Dendritic Cells - Copyright Prof Dirk Werling DrMedVet PhD MRCVS]]
===Antigen Presentation by Dendritic Cells===
*Dendritic cells present antigen to [[Lymphocytes - WikiBlood#T cells|T cells]]
*Circulating monocytes differentiate to form immature dendritic cells called '''Langerhans Cells'''
*Langerhans cells sample the tissue fluid by endocytosis
**Foreign organisms are internalised
** Within the dendritic cells, antigen is digested to peptides
** Some of the peptides formed bind to the cell’s [[Adaptive Immune System - WikiBlood#Structure and Function of MHC Class I|MHC]] molecules
*The Langerhans cells leave the epithelium and travel via the afferent lymph. They are now called '''Veiled Cells'''
*Veiled cells enter the paracortical region of the [[Lymph Nodes - Anatomy & Physiology|lymph node]] where they present antigen to [[Lymphocytes - WikiBlood#T cells|T cells]]. They are now called '''Interdigitating Dendritic Cells'''
==TH<sub>1</sub> Cells==
==TH<sub>1</sub> Cells==