Scientists have described a molecular switch that appears to determine where infection-fighting white blood cells travel inside the body, and, equally important, when they hold still.
The work, published in Science Advances and announced July 30, comes from a collaboration between Professor Randy Mrsny at the University of Bath’s Center for Drug Discovery and Professor Beth McCormick at UMass Chan Medical School. It concerns neutrophils, the most abundant white blood cells in circulation and the first immune cells to arrive at an infection.
Nothing here changes any treatment. There is no drug, no clinical trial, and no human testing. What the finding offers is a candidate target that the researchers hope could eventually support anti-inflammatory drugs that act only where inflammation is occurring, rather than suppressing it throughout the body.
A Brake, an Accelerator, and a Chemical Breadcrumb
The question the work addresses has been open in immunology for a long time. Neutrophils are destructive by design. They kill microbes by releasing enzymes and reactive chemicals that damage whatever is nearby. Yet they routinely travel long distances through healthy tissue in the gut and lungs to reach an infection without leaving a trail of injury behind them.
According to the announcement, the researchers describe a multistep sequence. Cells at an infection site release a short-lived fatty molecule called hepoxilin A3. A sensor protein on the neutrophil surface, TRPV2, detects it. TRPV2 then pairs with the type 2 cannabinoid receptor, CB2R, forming what the team calls a signaling complex that steers the cell specifically toward the hepoxilin A3 source.
The pairing is what makes the model interesting. Earlier work from the same group indicated that CB2R activation by the body’s own endocannabinoids suppresses hepoxilin A3-driven neutrophil movement, functioning as a brake when no infection is present. The new work describes the TRPV2 and CB2R complex as releasing that brake. Bath’s announcement compares the arrangement to linking an accelerator to a brake pedal.
The team also reports that neutrophils do not discharge their caustic contents while migrating, which would explain how they cross healthy tissue without collateral damage.
Mrsny described the cells in plain terms, saying that «neutrophils are cells that can act like bombs» once they reach an infection.
Decades of Groundwork Behind the Finding
This is not a first encounter with hepoxilin A3. Mrsny and McCormick identified the molecule as a neutrophil chemoattractant in a 2004 paper in the Proceedings of the National Academy of Sciences, describing it as the signal that draws neutrophils across intestinal epithelial barriers. Subsequent work from their labs and others extended the finding to airway epithelium infected with Pseudomonas aeruginosa.
The relevance of that lineage is that the new result adds a receptor mechanism to a chemical signal that has been studied for more than two decades. It is an incremental advance on a known pathway rather than the discovery of an unknown one, which is a reasonable thing for readers to understand when a release describes a system as previously unknown.
TRPV2 itself has been separately implicated in neutrophil function. A 2025 paper in the FASEB Journal from Hannover Medical School reported evidence that TRPV2 is involved in cytokine expression and transmigration in human neutrophils, and described the channel as a candidate target for drugs regulating neutrophil activity. That independent line of work is consistent with the direction of the new findings.
A Contested Piece of the Mechanism
One limitation deserves attention rather than a footnote. The role of hepoxilin A3 in neutrophil transepithelial migration has been publicly disputed in the scientific literature.
In 2020, biochemist Alan R. Brash published a letter in the American Journal of Physiology titled «Challenging the evidence for hepoxilin A3 being a mediator of neutrophil epithelial transmigration,» questioning the body of work implicating the molecule as the mediator of that process. That challenge concerns the foundation the new receptor findings are built on. It does not invalidate them, and the new work may strengthen the case, but readers should know the underlying pathway has active critics.
A second limitation is one MedicalDaily could not resolve. Publicly available announcements do not specify which experimental systems the team used, whether isolated human neutrophils, cultured epithelial barriers, animal models, or a combination. That matters for interpretation, because results from cells in a dish and results from a living animal support different levels of confidence. The claim that this describes how neutrophils move «through the body» should be read against that gap until the methods are examined.
Distance Between This Result and a Medicine
The gap between a receptor mechanism and a prescription is wide, and the researchers have not claimed otherwise. Their stated next step is investigating how the hepoxilin A3 pathway could be blocked, which is the beginning of drug discovery rather than the end of it.
Several things would need to happen before this reached patients. A molecule that blocks the pathway would have to be identified and shown to work in animals. It would need a safety profile, since suppressing neutrophil navigation carries an obvious infection risk that any candidate would have to manage. It would then need to move through human trials in sequence. Compounds at this stage frequently do not survive that process, and timelines are measured in many years.
The therapeutic rationale, if it holds, is genuinely appealing. Current anti-inflammatory drugs act broadly, which is why they carry systemic side effects. A treatment acting only on a locally released signal would in principle spare the rest of the body. That is a hypothesis about a drug that does not exist.
For anyone living with inflammatory bowel disease, chronic obstructive pulmonary disease, or another neutrophil-driven condition, the reasonable response to this news is interest without expectation. Nothing about current treatment should change, and no one should alter or stop a prescribed medication based on early-stage laboratory research. MedicalDaily will follow the pathway if candidate molecules enter animal or human testing.
Frequently Asked Questions
What did the researchers find? They describe a signaling complex formed by the TRPV2 sensor protein and the CB2R cannabinoid receptor that guides neutrophils toward hepoxilin A3, a molecule released by infected cells.
Why does neutrophil navigation matter? Neutrophils kill microbes with chemicals that also damage tissue. How they reach an infection without injuring healthy tissue along the way has been a long-standing question.
Is there a drug based on this? No. There is no drug candidate, no clinical trial, and no human testing. The team’s next step is investigating whether the pathway can be blocked.
Was this tested in people? No. This is laboratory research. Publicly available announcements do not specify the experimental systems used.
Is the underlying mechanism settled? No. The role of hepoxilin A3 in neutrophil movement across epithelial barriers was formally challenged in the scientific literature in 2020, and that debate remains open.
Which conditions could this eventually relate to? The researchers point to chronic inflammatory diseases of the gut and lung. Any application remains hypothetical.
Should patients change anything now? No. Nothing in this research affects current treatment, and no one should alter a prescribed medication based on early laboratory findings.
