MONTREAL — The molecule that shuts down the body’s cancer defenses does not need a middleman. It acts on its own.
That is the finding from Dr. André Veillette’s team at the Montreal Clinical Research Institute. Their paper, published in Nature, describes how SLAMF6 — a molecule on the surface of immune cells — triggers suppressive signals directly. No other molecule has to pass the message along. SLAMF6 binds to itself and weakens T cells from within.
This matters because current cancer drugs target a different system entirely. PD1 and PDL1 inhibitors strip away signals that tumors use to hide. They work for some patients. But many either never respond or eventually stop responding. The research team found that SLAMF6 keeps suppressing the immune response even after those other brakes are removed.
“It’s a previously unknown mechanism,” the report states. And it is a stubborn one.
The team created monoclonal antibodies that block SLAMF6 from binding to itself. In lab tests, those antibodies shut down the molecule’s suppressive signals. The researchers believe these antibodies could become the basis of a new treatment.
The discovery is a direct answer to a specific clinical problem. Cancer immunotherapy has been one of the most promising fields in oncology over the past decade. Drugs that release the immune system’s brakes have transformed treatment for melanoma, lung cancer, and other malignancies. But the drugs are not cures for everyone. Resistance develops. Tumors find new ways to hide.
SLAMF6 appears to be one of those ways. The molecule sits on the surface of T cells, the immune cells that hunt and kill cancer. When SLAMF6 binds to itself, it sends a signal that weakens the T cell’s attack. The team at IRCM has been studying this molecule and its role in immunotherapy for some time.
The antibodies they developed are designed to stop that self-binding. No binding, no suppressive signal. The T cell stays active.
The work is still in the lab. The antibodies have shown promising results in laboratory testing, but they have not yet been tested in human patients. That is the next step.
Dr. Veillette is a medical professor at the Université de Montréal. His team’s finding offers a new target for drug development. Most immunotherapy research has focused on molecules like PD1 and CTLA4. SLAMF6 works differently. It is not a receptor that waits for a signal from a tumor. It generates its own signal.
For patients who have already failed standard immunotherapy, this could matter. The new antibodies might work where PD1 inhibitors do not. The researchers believe the discovery could bring new hope to patients who have not responded to existing treatments.
The study was published in Nature, one of the most selective scientific journals in the world. That placement signals that the finding has passed rigorous peer review. The mechanism is novel. The potential application is clear.
Cancer treatments fail for many reasons. Tumors mutate. Immune cells exhaust. Suppressive pathways overlap. This finding adds a specific, targetable mechanism to the list. The team has developed a tool to block it. The question now is whether those lab results will hold in human bodies. That will take years of clinical trials to answer.
For now, the discovery stands as a precise piece of biological insight. A molecule that activates itself. A brake that works alone. An antibody that stops it.
