Waking Up the Immune System’s Sleeping Soldiers
Imagine there’s an art museum, and the guard on duty keeps dozing off. Art thieves come in. They step over the guard, who is now snoring, and steal a valuable painting. The guard had a gun, an alarm, and other anti-theft devices at his disposal, but never used them. All that untapped firepower was wasted.
In our bodies, certain white blood cells called lymphocytes are a lot like that guard. They have a great ability to attack and destroy enemies, including bacteria and cancer cells. But when the enemy is prostate cancer, for some reason, these lymphocytes — designed to destroy these cancer cells — don’t do their job.
White blood cells called lymphocytes
have a great ability to attack
and destroy enemies. But when
the enemy is prostate cancer, for
some reason, they don’t work.
Oncologist Charles Drake, M.D., Ph.D., the Phyllis and Brian L. Harvey Scholar, has figured out why. “Using a mouse model, we found a protein on the surface of some of these cells that might help explain this lack of function,” he says. This protein is called LAG-3, and “by blocking it, we were able to help lymphocytes move into prostate glands.” Basically, Drake and colleagues put the sleeping soldiers back into action, so they could help fight off prostate cancer. In other experiments, they combined LAG-3- blocking with a specific vaccine against prostate cancer, and this also jump-started the immune system, “causing lymphocytes to move into the prostate gland and destroy their target cells.” This work was published in the Journal of Clinical Investigation. Drake hopes to test this strategy in men with prostate cancer, “but first, we need to make a human version of the LAG-3 blocking agent,” called a monoclonal antibody. He and colleagues have teamed up with a leading biotechnology company to do this.