In a study recently published in Science Advances, Samir Mitragotri’s team at Harvard’s Wyss Institute engineered a new way to make one of the body’s own immune cells overcome a tumor’s defenses — the primary goal of immunotherapy.
The immune cells are macrophages, quick-change artists that can flip from attack mode (good for battling attackers like cancer) to healing mode (good for promoting growth), depending on chemical cues in the microenvironment around them. Tumors secrete substances to switch macrophages into the latter mode, making them their allies in spreading cancer. But Mitragotri’s group found a way to thwart the tumors: The team strapped cellular “backpacks” filled with interferon-gamma on the macrophages. A cytokine, the interferon stimulates inflammation and keeps macrophages in attack mode.