Scientists Engineer Unlimited Supply of Immune Cells to Combat Solid Tumors and Blood Cancer

Researchers from the University of Southern California and Stanford University have genetically engineered and cultivated an unlimited laboratory supply of precursor macrophage cells, a major breakthrough in cancer immunotherapy. Published in the journal Cell, the study reveals the precise chemical formula that enables these precursor cells to replicate indefinitely outside the body without losing their identity, overcoming a critical obstacle in growing macrophages for therapeutic use.

Macrophages, known as the immune system's "big eaters," play a key role in attacking cancer cells and activating other immune defenses. While CAR-T cell therapy has revolutionized treatment for blood cancers, it has been largely ineffective against solid tumors. Macrophages are abundant within solid tumors, making them ideal candidates for a similar approach called CAR-M therapy. However, macrophages have been difficult to genetically engineer and expand in the lab until now.

The research team, led by biologist Chi-Long Ying, shifted focus from mature macrophages to their precursor cells. By providing a complex chemical environment at specific developmental stages, they successfully produced powerful CAR-M cells. When injected into mice with blood and solid tumors, these engineered precursor cells spread throughout the body, continuously generating macrophages and other immune cells that halted tumor progression.

Stanford biologist Ravi Majeti highlighted that this method opens the door to numerous clinical applications, similar to the impact of engineered T cells. The researchers conclude that future cancer and immunotherapy treatments will depend not only on receptor design but also on selecting the optimal developmental stage of immune cells, potentially enabling large-scale production of therapies for cancer, infectious diseases, and other complex conditions.