The Bugs that Cure Disease

E. coli and Listeria monocytogenes aren't the first things you think about when you think about curing disease. But to some researchers at this year's ASM conference, these bugs are exactly what the doctor ordered. The Therapeutic Use of Genetically Engineered Bacteria symposium highlighted new ideas from biotech and academia that call for the use of pathogenic bacteria to fight many diseases, including cancer. Dirk Brockstedt from Aduro BioTech in California presented his company's attempt at turning Listeria into an effective cancer vaccine. Bacteria and viruses induce the body's immune system to attack, Brockstedt said, but cancer induces no such response. The idea is to genetically engineer Listeria to delete two of the genes that make it harmful to humans, introduce the double-delete mutants into a tumor, and — hopefully — watch the body's CD4 and CD8 T-cells go after the tumor as they would a bacterial infection. Brockstedt said Listeria's intracellular operation make it ideal for such a use. It's also easy and cheap to make and it isn't affected by antibodies, so you can use it over and over again, he added. The company is conducting Phase I trials in several different kinds of cancer as well as in hepatitis C.