Tuesday, October 04, 2011

Of Dreams and Dendritic Cells

"His dream was to use his discovery to cure cancer and infectious diseases like HIV and tuberculosis. It's a dream that's pretty close." Michel Nussenzweig on his fellow researcher Ralph Steinman.

When my mom was newly diagnosed with lung cancer, I brought her a bunch of "Conan the Barbarian" balloons with an encouraging note calling on her immune cell to rally to the job of eliminating the cancer (which she ultimately bested, living on another 18 years!). At the time, however, she was less than amused and huffily informed me that "There is nothing wrong with my white cells."

Immunotherapy, wherein a patient's own immune cells are primed to attack their invasive cancer, is a rapidly advancing area of cancer research. Due to a wide array of ploys with which cancer cells hide from the immune system coupled with various host deficiencies in mounting the appropriate defense, cancer therapy has for years centered instead on chemotherapy. These toxic chemicals are designed to be more lethal to the rapidly dividing cancer cells than on normal tissue. Unfortunately, normal often falls along with the malignant.

One of the giants among researchers in immunotherapy is Ralph Steinman who ironically died September 30th, three days before winning the Nobel Prize in medicine earlier this week. In a further twist of fate, he died of pancreatic cancer, living much longer than most unfortunate souls with this disease perhaps because he applied his own discovery to his personal case.

Dr. Steinman's contribution to this important research was the identification of a unique little player in the immune cascade that he dubbed a dendritic cell due to its tree-like branching configuration reminescent of the dendrites of neurons. The dendritic cell is one of the initial workhorses of the immune system, processing foreign material such as viruses and then presenting it to T cells which are activated in turn to attack the unwelcome invaders.

Dr. Steinman isolated his dendritic cells, exposed them to his pancreatic cancer cells, and thus instructed his T cells to recognize those bad boys as unwanted visitors. A former student, now a collaborator, had this to say, "We'll never know [whether it worked] ...but one thing is for sure: he was able to make T-cells specific for his cancer. It obviously didn't cure him, but it may have prolonged his life."

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