Researchers at Washington University School of Medicine in St. Louis report that an antibody aimed at a protein called CXCR3 protected the brains of mice carrying Alzheimer's-like tau tangles - not by clearing the tau, but by keeping immune cells out. Over several months of injections, the treatment cut the number of T cells in the brain roughly in half by blocking the route those cells use to get in.
The animals that received the antibody retained about 40% more tissue in memory-related brain regions and performed better on a memory test than untreated mice. Tau levels themselves were unchanged, which is the part worth pausing on: it supports the idea that in tauopathies, much of the cell death near tau clumps is driven by the immune system's reaction to the protein rather than by the protein alone.
That distinction matters for how future drugs might be designed. Most experimental approaches in this space go after the abnormal proteins directly. If the damage is largely an inflammatory response, then a treatment that leaves tau in place could still spare neurons. As the team framed it, no current treatment for tauopathies actually decreases neurodegeneration, and a pathway that demonstrably reduces brain cell death is worth pursuing.
This is mouse work, and the antibody was given over an extended period in animals engineered to accumulate tau. Whether the same immune route behaves this way in human brains, and whether suppressing T cell entry over years is safe, are open questions that the research does not answer.