Engineers at the University of Pennsylvania have developed a new type of lipid nanoparticle (LNP) that could one day serve as a universal immunotherapy for cancers that form solid tumors, including common variants such as cancers of the breast, liver, and colon.

One of the greatest challenges in immunotherapy is the exhaustion of T cells, the white blood cells responsible for detecting and destroying cancer cells. Many tumors produce an enzyme called IDO that dampens immune activity. Over time, exposure to the harsh environment inside tumors further weakens T cells.

The new particles counter both effects at once. By delivering a drug that blocks IDO together with mRNA that instructs cells to produce an immune-activating protein, the engineered nanoparticles reinvigorate exhausted T cells, enabling them to attack tumors without the need for costly and time-consuming, patient-specific adjustments.