I'm interested in how dendritic cells present antigens to helper T-cells? I'm also interested in the molecular actions between a dendritic cell and a helper T-cell during the activation of the helper T-cell? What function does the homing receptor on a T-cell have?
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$\begingroup$ what is your question? $\endgroup$– AliceD ♦Apr 2, 2015 at 13:06
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2$\begingroup$ In the inflammatory response, dendritic cells mainly function as antigen-presenting cells, but the homing phenomenon happens under normal (non-inflammatory) conditions. Note that this is different from immune cell recruitment to the site of inflammation. You should specify under which context you'd like to know DC function. $\endgroup$– SleepsesApr 2, 2015 at 14:23
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1$\begingroup$ @poka.nandor I must say the probability is high you are a good in-between lines reader :)... That edit... $\endgroup$– cagliari2005Apr 2, 2015 at 15:13
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1$\begingroup$ @cagliari2005 - Thanks :) This seemed the most logical intention (at least for me) of the question based on title and the short description provided. $\endgroup$– Nandor PokaApr 2, 2015 at 15:16
1 Answer
Dendritic cells are so called professional antigen-presenting cells (APCs) as pointed out by Sleepes in comment section. They express both MHC-I and MHC-II receptors on their cell surface on which they present small peptides. These small peptides come from digested proteins of their own (MHC-I) or antigens that were phagocited or taken up by receptor mediated endocytosis (MHC-II). They also express costimulatory molecules necessary for the activation of T-cells (eg. CD80/CD86).
source: http://journals.cambridge.org/fulltext_content/ERM/ERM2_09/S1462399400002143sup004.htm
As you can see in image above, activation of a T-cell requires two distinct signals: the recognition of an antigen and a co-stimulatory signal.
source: http://www.mhhe.com/biosci/ap/dynamichuman2/content/gifs/0158.gif
After activation T-cells undergo rapid division and diversification.
Details of T-cell activation by dendritic cells can be found in this article for example: Immunol Cell Biol. 1997 Jun;75(3):223-30. The role of dendritic cells in T cell activation. Ni K1, O'Neill HC.