New CAR-T Therapy Turns Brain Cells Into Alzheimer’s Plaque-Clearers

Researchers at Washington University School of Medicine in St. Louis have developed a cellular immunotherapy that engineers brain cells to identify and remove amyloid beta plaques, a hallmark of Alzheimer’s disease. This approach utilizes astrocytes, which are abundant support cells in the brain, transforming them into specialized cleaners to target toxic protein clumps.

The study, published on March 5, 2026, in the journal Science, describes a method that equips astrocytes with a CAR (Chimeric Antigen Receptor) homing device. This technology is adapted from CAR-T cell therapies used in cancer treatment, where immune cells are genetically modified to attack specific tumor cells.

Mechanism and Results in Mouse Models

The engineered CAR-astrocyte cells are designed to grab onto amyloid beta plaques for destruction. In mouse models of Alzheimer’s disease, the researchers found that a single injection of this therapy could prevent amyloid plaques from developing if administered before the plaques began to form.

For mice that had already developed plaques, a single treatment reduced the amount of amyloid plaques by half. This represents the first successful attempt to engineer astrocytes specifically to target and remove these plaques in the brains of mice with Alzheimer’s disease.

Comparison to Current Treatments

This cellular immunotherapy differs significantly from the current generation of Alzheimer’s drugs, such as monoclonal antibodies. While monoclonal antibodies are proven to change the course of the disease by reducing amyloid accumulations, they typically require high-dose infusions once or twice every month.

The CAR-astrocyte approach aims to reduce the frequency of treatment and potentially improve efficacy by using a single injection to create a lasting presence of plaque-clearing cells within the brain.

Parallel Research into CAR-T Cell Therapy

Alongside the astrocyte research, another team led by Dr. Jonathan Kipnis at Washington University School of Medicine has explored using engineered T cells to treat the disease. This research, published February 9, 2026, in the Proceedings of the National Academy of Sciences (PNAS), focused on CAR-T helper cells.

These engineered T helper cells were designed to recognize and lead to the breakdown of amyloid plaques. In mouse models, this therapy reduced several hallmarks of the disease, including:

• Amyloid plaques
• The activation of brain-specific immune cells
• Damaged nerve cells

To address safety concerns regarding prolonged immune activation, researchers also tested a transient, mRNA-based version of the CAR-T therapy. This shorter-lived strategy reduced plaque load and decreased markers of neuronal damage, microgliosis, and astrogliosis.

Future Directions and Limitations

While the results in animal models are promising, the researchers emphasize that further development is required. Senior author Marco Colonna, MD, noted that more work is needed to optimize the approach and address potential side effects before this could be transitioned to human patients.

Although more work needs to be done to optimize the approach and address potential side effects, these results open up an exciting new opportunity to develop CAR-astrocytes into an immunotherapy for neurodegenerative diseases and even brain tumors.

Marco Colonna, MD

The versatility of these engineered cells suggests they could eventually be adapted to deliver therapeutic agents for other neurodegenerative conditions beyond Alzheimer’s disease. The goal is to move toward therapies that can not only destroy plaques but potentially improve cognitive symptoms associated with the disease.