Scientists at the University of Southern California (USC) have cracked a major manufacturing challenge in cancer immunotherapy: how to produce a reliable, renewable supply of cancer-fighting immune cells. Instead of working with fully mature immune cells — which are hard to multiply, difficult to modify, and don't last long in the body — the team focused on immature precursor cells called granulocyte-monocyte progenitors (GMPs). Under carefully controlled lab conditions, these cells can self-renew indefinitely while retaining the ability to develop into functional immune defenders like macrophages.

The researchers genetically engineered GMPs with chimeric antigen receptors (CARs) — the same technology used in existing CAR-T cell therapies — to help them recognize and attack tumors. In mouse models, the engineered cells settled into bone marrow, kept producing fresh immune cells, and slowed the progression of both blood cancers and solid tumors. An added immune-activating signal boosted results further and even worked across mismatched donor-recipient pairs, hinting at the possibility of ready-made, off-the-shelf treatments.

Key Takeaways:

• GMPs can self-renew in the lab — a property previously thought to belong only to stem cells — offering a scalable starting point for cell therapies
• CAR-engineered GMPs slowed cancer progression in mice with both blood cancers and solid tumors
• The approach may also apply to inherited immune disorders like chronic granulomatous disease

Why it matters: Current CAR-T therapies are expensive, time-consuming, and personalized to each patient. A renewable GMP-based platform could make immunotherapy faster to produce, more widely available, and potentially effective against hard-to-treat solid tumors.