![](https://webarchive.library.unt.edu/eot2008/20090514050600im_/http://www.cancer.gov/images/spacer.gif) |
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![](https://webarchive.library.unt.edu/eot2008/20090514050600im_/http://www.cancer.gov/images/spacer.gif)
| A substance that activates some types of immune system cells, and is being studied as a treatment for cancer. It belongs to the family of drugs called biological therapy agents. |
Previous Definitions: | viral vector, virotherapy, virtual colonoscopy, virulence, virulent | Next Definitions: | virus, virus replication cycle, virus-neutralizing antibody, viscera, visceral |
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