Luminescent Probe Measures Immune Cell Activity in Real Time

Current methods cannot measure immune cell function directly and in real time, making it difficult to tailor immunosuppressive or immunotherapy regimens to individual patients. Now, a new luminescent probe offers a way to observe immune activity as it happens, enabling highly personalized medical interventions and advancing precision medicine.

Researchers from the University of Granada (Granada, Spain) and Mount Sinai Hospital (New York, NY, USA) have developed GLed, a groundbreaking molecular probe that can monitor immune system activity live and with exceptional sensitivity. Acting as a “molecular beacon,” the probe lights up upon detecting glutathione, a key antioxidant molecule that signals cellular activity levels. Its most distinctive feature is reversibility—it switches on and off dynamically—allowing scientists to track real-time fluctuations in T cell function with unmatched speed and precision.

In a study published in Advanced Science, the researchers used GLed to investigate how glutathione production is regulated during T cell activation. Results revealed that the enzyme gamma-glutamyl cysteine ligase (GCL) is solely responsible for producing new glutathione in active human T cells. When GCL was inhibited, T cells lost their ability to multiply and secrete inflammatory molecules, demonstrating the enzyme’s essential role in immune response regulation.

Researchers also applied GLed to assess the effects of commonly used immunosuppressive drugs such as prednisone and tacrolimus. The probe showed that these drugs reduce GCL activity in proportion to their immunosuppressive strength, providing the first direct and functional measurement of immune suppression in living cells. This capability could allow clinicians to adjust drug dosages precisely for each patient, improving treatment safety and efficacy.

In addition to its clinical utility, GLed offers powerful new possibilities for basic research in immunology, inflammation, and oncology. Its use in functional monitoring may transform how immune-related diseases are studied and treated. Over time, integrating this probe into clinical settings could revolutionize transplant medicine and immunotherapy by making immune function tracking as routine as blood tests.

Related Links:
University of Granada
Mount Sinai Hospital