🧬 Scientists May Have Found a New Way to Mass-Produce Cancer-Fighting Immune Cells

For more than a decade, cancer immunotherapy has been dominated by T cells. CAR-T therapies can be powerful against some blood cancers, but they remain expensive, highly personalized, and much harder to use against solid tumors.

Now researchers at USC Stem Cell have shifted attention to a different immune lineage: granulocyte-monocyte progenitors, or GMPs — early precursor cells that can produce macrophages, the immune system’s “first responders.”

Macrophages are especially interesting because they naturally enter tumors, engulf abnormal cells, and help coordinate immune responses. But mature macrophages are difficult to grow in large numbers, hard to genetically engineer, and not ideal for freezing and storage.

The USC team worked one step earlier — with GMPs before they mature. Using a defined chemical cocktail, they managed to keep mouse and human GMPs in a progenitor-like state while allowing them to expand long-term in the lab. That is important because long-term self-renewal in the blood system was traditionally associated mainly with true hematopoietic stem cells, not more committed progenitors.

Then the researchers engineered these GMPs with CAR receptors so they could recognize cancer cells. They also added a CAR-Fc design that can recruit other immune cells and help activate broader anti-tumor responses.

In mouse experiments, the engineered GMPs settled into bone marrow and other blood-forming tissues, where they continuously generated tumor-infiltrating macrophages and other myeloid cells. The cells suppressed CD19-positive leukemia and HER2-positive solid tumors, and the dual CAR-Fc design showed stronger effects in allogeneic cancer models.

The same platform also restored antibacterial defense in mice with chronic granulomatous disease, an inherited immune deficiency disorder.

Why this matters: this is not just another CAR-T variant. It is a possible manufacturing breakthrough for an entirely different branch of the immune system — one that may be better suited for solid tumors and potentially easier to produce as an off-the-shelf therapy.

The important caveat: these are still preclinical results in mice. The real test will be whether the platform is safe, durable, and effective in humans.

But the idea is powerful: instead of only engineering mature immune cells, scientists may be learning how to grow a renewable upstream factory that keeps producing cancer-fighting cells from inside the body.

Paper: Cell
https://www.cell.com/cell/fulltext/S0092-8674(26)00643-4

Summary: ScienceDaily
https://www.sciencedaily.com/releases/2026/06/260620100317.htm

#Immunotherapy #Cancer #StemCells #CellTherapy #Biotech