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  First the macrophages attack the allergin in the celular fluid.
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  How the immune system reacts to an allergen,
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  The body then recognizes the allergen and engulfs the allergen; eating it with the macrophage.
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  Next the macrophage that engulfed the allergen present itself to a T-Cell.
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  Next this T-Cell containing a bit of the allergen turns into varieties of that T-Cell and causes the immune system rally up.
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  Next the B-Cells in the immune system will recognize the T-Cell and be the memory of what is inside the T-Cell.
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  The B-Cell then duplicates itself a various amount of times in order for the body to be able to recognize the threat in the future.