German scientists have reported a new way of adapting immune cells to combat cancer.
The scientists in Munich have adapted a surface molecule found on T cells with a view to improving the response to cancer.
The molecule causes the cells to respond particularly aggressively when they encounter a protein that tumours use to camouflage themselves from the immune system, according to a new study published in Cancer Research.
Led by Professor Dr Elfriede Nößner, head of the Tissue Control of Immunocytes Research Group at the Helmholtz Zentrum München, the research focuses on the body’s own immune system to help combat cancer.
“Because cancer emerges from the body’s own cells, it is usually difficult for the immune system to distinguish good cells from bad ones,” she said. “But there are ways to support the immune system in recognising and combating cancer cells.”
One approach is adoptive T-cell therapy, which removes immune cells from the body so that they can be given new structures on the surface, which guide them to the cancer cells. However, there are limitations to this, said Prof Nößner.
“Although this binding can be artificially strengthened, doing so also increases the risk of unwanted binding to healthy structures in the body,” she explained.
To prevent that, she and her team looked for a different way to improve the defence provided by the immune cells.
They developed a new surface molecule, which on the outside, preferentially binds to the PD-L1 molecule, which tumour cells often form in order to thwart the attacking immune cells. On the inside of the T-cells, the binding does not activate a sleep mode and instead activates the T-cell’s killer programme.
Experimental models showed that T-cells armed in this way proliferate more strongly in the tumours and destroyed more tumour cells.
The next step will be to confirm the findings in clinical studies, said Prof Nößner.
“If that step succeeds, the approach would enlarge the arsenal of T-cells suitable for adoptive T-cell therapy. This could not only make the treatment more effective but would allow it to be used in more patients in the framework of personalised medicine,” she added.
Schlenker, R. et al. (2017): Chimeric PD-1:28 receptor upgrades low-avidity T cells and restores effector function of tumor-infiltrating lymphocytes for adoptive cell therapy. Cancer Research 8 June 2017; doi: 10.1158/0008-5472.CAN-16-1922
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