Every human being has the capability to recognize and accept what belongs to his own body, the 'self'', an to recognize and reject what foreign, the 'non self''.(Dakroub, 2011)
Marker of 'Self'': the HLA System
the 'self'' is determined by a set of molecules , specific to each individual , that are expressed on the membrane of nucleated cells*. The most important ones are the proteins of the Human Leukocyte Antigen(HLA) system. They are genetically determined and called '' markers'' because they represent a''biological identity card' unique to each individual.HLA molecules are identical on all cells of single and different from one person to another(Dakroub, 2011).
* nucleated cell: cell that has nucleus.
'Non-Self''Non -Self encompasses all that is recognized by the body as being different from 'self'. It includes allergens (non-harmful substances), pathogens( microbes and their products), cells and tissues of the other individuals, but also own cells and tissues, if they are modified by an infection or a cancerous transformations*.
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Retrieved November 27, 2014, from http://img.thebody.com/nih/2006/cancer2.jpg
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* Cancerous transformation: uncontrolled and abnormal divisions of a cell.The immune system is able to distinguish between ''self'' molecules, that it will tolerate, and 'non-self' molecules that is will reject. All these rejected molecules are called antigens*.
* Antigens: substance that is specially recognized by the immune system as foreign body.
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| Markers of the Non- Self .The National Cancer Institution.Retrieved November 27, 2014, from http://img.thebody.com/nih/2006/cancer3.jpg Refercences Dakroub, R. N. (2011). Life and Earth Sciences. Lebanon, Sin El Fil: center for educational resarch and Development, Educational Company. |
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