Macrophages are white blood cells that play a key role in helping to protect us against microscopic threats, from infections to cancer. These cells constantly survey the body’s tissues and consume pathogens, debris, dead cells and cancer. To do this they scan for “eat me” signals such as IgG antibodies.
It’s critical that patrolling macrophages ignore healthy cells, otherwise they could trigger an autoimmune response. In an in vitro study designed to help understand how macrophages choose what and when to eat, researchers at UC Santa Barbara (UCSB) programmed these immune cells to respond to light, offering up the opportunity to investigate how encounters with cancer cells changed the macrophages’ appetite. They found that they could “prime” the macrophages to subsequently eat more IgG-bound human cancer cells.
“We discovered that giving macrophages an appetizer makes them hungrier for their next meal,” said Meghan Morrissey, PhD, an assistant professor in the department of molecular, cellular, and developmental biology. The team suggests their results could point to a new way to increase the effectiveness of cancer immunotherapies that harness macrophages to combat the disease. The findings also present a more complex account of trained immunity, a kind of memory exhibited in the innate immune system that scientists have only recently recognized.
Morrissey is senior author of the researchers’ published paper in , titled “ .” In their report the team c.