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The human immune system is supported by various immune cells and also by other secretions, that is, humoral secretions of the body, in order to evade the pathogens that tend to attack the human body continuously.
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And these pathogens can get access to a human body via different roots.
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For example, it can come in contact with a skin surface or it can be present in the food or it can be present in the water.
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So these are the three major sources using which a pathogen can come in direct contact with the body and can make a person immunologically weak and result in a condition that is called as a disease.
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That is this denotes the establishment of the pathogen in a particular human individual.
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This can be avoided by the support of cells which are called as the immune cells.
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So these immune cells are made from a precursor cell which is called as a precocious cell which is called as a pluripotent hematopoietic stem cell.
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Let's write it as p -hc, pluripotent hematopoetic stem cells.
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So this pluripotent hematopoetic stem cells will give rise to two lineages.
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The first one, it is called as the myeloid lineage and the second one is called as the lymphoid lineage.
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So let's see the lymphoid lineage in detail.
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This lymphoid lineage will give rise to four important types of cells.
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They are the first one.
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It is called as the dentritic cell.
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Dentritic.
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Cell is one of the phagocytic cell and play a key rule in destroying the particular pathogen.
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Next to it, it is called as the natural killer cell, which is written as nk cell...