Scientists at USC Stem Cell have developed a breakthrough method for creating a renewable, expandable supply of immune cell precursors that could transform cancer immunotherapy and the treatment of immune disorders.
Published in the journal Cell, the research focuses on granulocyte-monocyte progenitors (GMPs), cells that produce macrophages and other immune cells. The team discovered that, under the right chemical conditions, GMPs can be made to self-renew indefinitely in the lab — a property traditionally reserved for stem cells.
"The prevailing view has been that long-term self-renewal in the blood system is primarily a property of hematopoietic stem cells," said Dr. Qi-Long Ying, the study's corresponding author. "We found that, under the right conditions, GMPs can also self-renew, dividing extensively while keeping their identity and ability to produce functional immune cells."
The researchers engineered these GMPs with a chimeric antigen receptor (CAR) to recognize cancer cells, plus a second signal that activates nearby tumor-fighting T cells. This second signal works even when donor and recipient cells are immunologically mismatched, raising the possibility of off-the-shelf therapies.
In mouse studies, the CAR-engineered GMPs successfully slowed both blood cancers and solid tumors. The platform also showed promise for chronic granulomatous disease, an inherited immune disorder, restoring the animals' ability to fight bacterial infections.
"Our study suggests that the future of immunotherapy may depend not only on designing better CAR receptors, but also on choosing the right developmental stage of the cell," Ying said.
Stanford University researchers independently validated the findings, reinforcing the platform's reliability. The team has filed patents and co-founded Myelogene Inc. to commercialize the technology.
