When Bad Bugs Go Good

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To make that work, the researchers needed huge quantities of EBV. That wasn't a problem, since the infected cells grow abundantly in culture. "You can get bucketloads of them," says Cliona Rooney, an immunovirologist at the Texas Medical Center. Rooney's group modified EBV-infected cells to wear a protein that is shared by three different types of cancer--a devastating form of throat cancer as well as Hodgkin's disease and non-Hodgkin's lymphoma, both cancers of the lymph system. Using separate culture dishes of those cells for each patient, she added T cells extracted from each patient's blood and selected just the ones that homed in on the viral and cancer proteins. Those specialized T cells were then injected back into patients, giving their defenses a boost of reinforcements. "We have seen some remissions in all three groups of patients," Rooney reports. "We are working on ways to make our approach more potent and useful for other types of cancer."

Viruses are not the only microbes being rehabilitated for good works. Following the lead of the millions of Botox devotees who regularly benefit from injections of one of the world's deadliest toxins--botulinum--scientists at Johns Hopkins were inspired to look more closely at the botulinum-producing clostridium family. They matched one of the bacterium's unique features--it flourishes under low-oxygen conditions--with one of a malignant tumor's most vexing characteristics: it continues to divide extremely well with little or no oxygen. "The trick to using bacteria or viruses therapeutically is to have them exploit something unique to the cancer cell," says Kinzler, who is co-directing the studies. Kinzler and his colleague Bert Vogelstein have altered the clostridium to replicate only in the oxygen-starved depths of a tumor. Once there, the bacterium's natural toxins are released and quickly eat through the malignant growth. So far, the scientists have tested their therapy only in mice, but the results have been impressive.