defined: |
![](https://webarchive.library.unt.edu/web/20090813010608im_/http://genome.gov/Images/spacer2.gif) |
A small white blood cell that plays a major role in defending the body against disease. There are two main types of lymphocytes: B cells, which make antibodies that attack bacteria and toxins, and T cells, which attack body cells themselves when they have been taken over by viruses or become cancerous.
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