adaptive immune response, is based on recognizing and remembering molecules which pose a threat. After fighting off the initial assault, the body "remembers" the pernicious molecule via the long-lived memory T- and B-cells. The next time your body is exposed to the molecule, an overwhelming army of immune cells are poised for attack. This immunological memory is the scientific basis for vaccination. [ Berezow 12 ] The human immune system is incredibly complicated, and it involves several organs (e.g., thymus, lymph nodes, spleen) as well as multiple cell types (e.g., T-cells, B-cells, macrophages, etc.). Bacteria aren't nearly as complex as humans, yet they too, have an adaptive immune system. How does it work?
Remarkably, the bacterial adaptive immune system, known as CRISPR (don't worry about what it stands for) is based on a similar principle: Recognizing and remembering foreign invaders.  [ Berezow 12 ]

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