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How a gang of thugs could cure cancer
09 February 2002
From New Scientist Print Edition.
Philip Cohen

Hordes of killer cells intent on destroying cancerous or infected cells could one day be injected into patients, thanks to a breakthrough that makes it far easier to grow them outside the body.

Our bodies naturally produce killer cells, also known as cytotoxic T lymphocytes or CTLs, which target tumours or virus-infected cells. But the immune response is sometimes too weak or patients are too ill to produce enough CTLs. So in experimental treatments called adoptive immunotherapy, specific immune cells from a patient are purified, encouraged to multiply and then reinjected. However, doctors are struggling to make such treatments practical. The cells require months of growth with special protein factors or a complex mix of companion "feeder" cells.

Now Carl June of the Abramson Family Cancer Research Institute in Philadelphia and his colleagues have designed a better cell to nurture CTLs, by decking an antigen-presenting cell's surface with a smorgasbord of proteins thought to encourage CTL growth.

The new improved CTL companions, which June calls artificial antigen-presenting cells or aAPCs, generated 400 times more CTLs than the most popular purified protein factor, and unpublished data suggests they are just as efficient as feeder cells—the gold standard in this field. What's more, from a patient immunised with flu vaccine, June's team was able to grow a full dose of CTLs in just 30 days that should kill flu-infected cells.

Mark Dudley, an adoptive immunotherapy researcher at the National Cancer Institute in the US, says aAPCs are a major advance. "Because they are so easily altered, these cells will allow a systematic way to find out how to generate the best CTL responses," he says. June hopes to be ready for a trial in a few years. And he thinks his team could eventually use aAPCs to produce enough CTLs in just two weeks. "Sometimes this therapy is used to treat really sick patients," he says. "And they can't wait any longer."

From issue 2329 of New Scientist magazine, 09 February 2002, page 14

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