New Delhi, April 4 : US researchers have engineered a new 'smart' immune cell that when activated by ultrasound can continuously sense and destroy cancer cells for extended periods.

The 'EchoBack CAR T-cell,' developed by biomedical engineers at the University of Southern California (USC), could soon be a game changer in the field of cancer immunotherapy.

The study, published in the scientific journal Cell, demonstrates that the powerful new EchoBack-CAR T-cells can attack tumour cells five times longer than regular CAR T-cells, in technology ready for medical applications.

The cells can be remotely controlled to target tumours using focused ultrasound, potentially making treatments safer yet more effective.

The novel approach could overcome major obstacles in treating tumours that are not usually candidates for immunotherapy, while keeping healthy tissue safe, said the team.

Unlike the first-generation, ultrasound-controllable CAR T-cells which usually only attack cancer cells for up to 24 hours before expiring, lead author Longwei Liu, Assistant Professor at the USC Viterbi School of Engineering, said that the EchoBack CAR T-cells function by being activated by ultrasound in the tumour location.

From there, the CAR T-cells continue to seek and destroy cancer cells for at least five days without fatiguing.

'You can imagine that when patients come to the hospital using the first-generation cells, the patient may need to come in every day for treatment. But using the new generation, the treatment now requires far fewer visits, such as once every two weeks, or even less frequently,' Liu said.

The team focused on ultrasound technology, which works as an 'on switch' for the CAR T-cells -- engineered to respond to a short 10-minute pulse of ultrasound. That then triggers the cells to sense cancer cells in their surroundings.

The new CAR T-cells were analysed, in lab-based experiments in mouse models, on a selection of tumour cells including prostate cancer and glioblastoma.

'We can clearly see that the ultrasound controllable CAR plus two rounds of ultrasound stimulation outperformed the standard CAR T-cells,' Liu said. 'Also, when we kept challenging our CAR T-cells with tumour cells, the standard CAR was already exhausted and in a dysfunctional state, but our ultrasound controllable CAR has a better function, less exhaustion, and more enhanced killing.'

/IANS