Researchers at a university used cryo-EM to study how the T cell receptor (TCR) begins signalling that leads to cancer cell killing. The work aimed to explain why current T cell immunotherapies work for some cancer subtypes but not others. The team found the receptor in a closed, compact state when resting and observed it open and extend when it encountered an antigen-presenting molecule.
The group made two key methodological changes. They returned the multi-protein complex to a membrane using nanodiscs and chose a lipid mixture that resembled the native T cell membrane. Getting all eight proteins properly assembled into the nanodisc was difficult. Earlier studies used detergent, which removed the membrane and apparently left the receptor in an open state even when dormant.
Lead researchers said the new structural view could help refine and expand T cell therapies. They suggested it might be possible to re-engineer receptor sensitivity and tune activation thresholds for adoptive T cell therapies used in some rare sarcomas. The structures could also inform vaccine design and allow others to study detailed interactions between HLA-presented antigens and T cell receptors.
Difficult words
- receptor — protein on a cell that detects signalsT cell receptor
- membrane — thin layer around cells or cell partsT cell membrane
- antigen — substance that triggers immune response in bodyantigens
- assemble — to put parts together to make wholeassembled
- detergent — chemical used to remove oils and fats
- sensitivity — how easily something reacts to a signal
- nanodisc — small artificial piece of membrane for studynanodiscs
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How might changing receptor sensitivity affect T cell therapy for patients?
- What challenges do you think scientists face when assembling eight proteins into a nanodisc?
- How could detailed structures of T cell receptors and HLA-presented antigens help vaccine design?
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