Scientists have created a molecular labeling method to track tuberculosis glycans, paving the way for simpler, quicker diagnostic tests.
MIT chemists have pioneered a technique to label a key glycan in Mycobacterium tuberculosis, the bacterium responsible for tuberculosis (TB). This breakthrough, published in the Proceedings of the National Academy of Sciences, could lead to faster and more affordable TB diagnostics, particularly in resource-limited regions where the disease remains a leading killer.
The team focused on a glycan called ManLAM, which is critical to TB’s ability to evade the immune system. By using a small organic molecule (oxaziridine) that binds to sulfur-containing sugars unique to TB, they successfully labeled and visualized ManLAM within bacterial cell walls. This method, which avoids genetic engineering, marks the first selective labeling of a specific TB glycan.
Current TB diagnostics, such as sputum cultures or chest X-rays, are slow, costly, or inaccessible in high-burden areas. The new approach could enable urine-based tests that detect ManLAM with higher sensitivity than antibody-based methods. “This could revolutionize TB diagnosis, especially for children and immunocompromised patients,” says lead author Stephanie Smelyansky.
- The labeling technique revealed that ManLAM persists in bacterial cell walls during early infection, challenging assumptions about glycan shedding.
- No signal was detected in non-pathogenic bacteria, confirming the method’s specificity for TB.
- The tool could also aid research into TB’s immune evasion and antibiotic resistance.
The team plans to adapt the labeling method for diagnostic use and explore its applications in studying TB cell wall assembly and host interactions. Senior author Laura Kiessling emphasizes, “This tool opens doors to understanding processes we couldn’t see before.” With TB claiming over 1 million lives annually, this innovation offers hope for quicker detection and better research tools. The study underscores MIT’s commitment to tackling global health challenges through cutting-edge chemistry.
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