Immunotherapies for cancer rely on recruiting the patient’s immune system, but they still fall far short of tapping into the entire arsenal of the body’s natural defenses. In fact, most such therapies draw on one type of immune defense: the ability of T cells to battle the tumor. A new study at the Weizmann Institute of Science, published in Cell, paves the way toward an immunotherapy that will exploit a different, previously unused immune system weapon: naturally produced antibodies.