Spinal cord injuries, with their devastating impact on mobility and quality of life, currently lack effective treatments. However, a groundbreaking study from Washington University School of Medicine offers a glimmer of hope. By harnessing the power of the immune system, researchers have developed a promising immunotherapy that protects neurons and improves recovery in mice with spinal cord injuries.

This new research, recently published in Nature, highlights a novel immunotherapy that, in mice, protects neurons from the damaging effects of immune cells after a traumatic spinal cord injury. By minimizing the body's self-destructive response, this therapy could revolutionize how spinal cord injuries are treated, potentially improving recovery outcomes for patients.

“Immune cells in the central nervous system have a reputation for being the bad guys that can harm the brain and spinal cord,” said Jonathan Kipnis, PhD, senior author of the study and the Alan A. and Edith L. Wolff Distinguished Professor of Pathology & Immunology at WashU Medicine. “But our study shows that it’s possible to harness immune cells’ neuroprotective abilities while controlling their harmful side, offering a new way to support recovery from central nervous system injuries.”

Rewiring the Immune System to Protect Neurons

When the nervous system suffers trauma, immune cells rush to the scene, including activated T cells—a type of immune cell that can either help or harm neurons. Wenqing Gao, PhD, lead author of the study and postdoctoral research associate at WashU Medicine, set out to unlock the mystery behind these cells. By analyzing T cells from the spinal cords of injured mice, she aimed to separate the harmful ones from the protective ones. Her goal? Multiply the beneficial T cells and use them to treat spinal cord injuries.

But there was a challenge. The same protective T cells that help initially can become overzealous, leading to autoimmune issues. Gao’s solution was to engineer these T cells to deactivate after a few days, ensuring they wouldn’t attack healthy tissue.

The results were striking. Mice treated with these modified T cells had better mobility than untreated mice. The treatment was most effective when administered within a week of the injury, and none of the mice developed autoimmune complications—a key breakthrough in ensuring the therapy’s safety.

“There are no effective treatments for traumatic injuries to the central nervous system,” said Gao. “Our immunotherapy dramatically improved mobility in mice, and we believe it has the potential to offer new hope for patients with spinal cord injuries.”

From Mice to Human Trials

To further validate their findings, the researchers collaborated with spinal cord surgeon Dr. Wilson Zachary Ray at WashU Medicine. They examined the cerebral spinal fluid of patients with spinal cord injuries, looking for T cells. Their research confirmed that the same type of protective T cells found in mice could be expanded in human patients, setting the stage for potential clinical trials.

“Our next step is to devise a clinical trial to test this therapy in humans,” Gao explained. “And we’re also excited to explore its potential in treating neurodegenerative diseases such as ALS, Alzheimer’s, and Parkinson’s.”

Kipnis added, “Even though the initial cause of neuron death in these diseases is different, similar immune processes may be at play. This opens the door to adapting our engineered T cells as a therapy for a wide range of neurodegenerative conditions.”