London, Jan 8 (IANS): In a major breakthrough, researchers have identified how a subset of immune cells are activated to kill cancerous cells, which could hold the key to new powerful therapies against cancer.

This new study built on previous research which found that following immunotherapy some CD4+ T cells, traditionally thought to be 'helper' and 'regulator' immune cells, become cytotoxic and directly engage with and kill cancer cells.

Published in the journal Immunity, the research team from University College London, examined the molecular and cellular mechanisms underpinning this activity, as part of an experimental study of immunotherapy in mice.

Researchers found that IL-2, a 'growth factor' for T cells and the 'transcription factor' Blimp-1 are responsible for initiating potent killer activity in CD4+ T cells within cancerous tumours.

"We knew these immune cells had the ability to proactively kill cancer cells with incredible potency, but to maximise their potential, we needed to know how this mechanism was activated," said study co-lead author Sergio Quezada.

"Our discovery provides the evidence and rationale for utilising Blimp-1 to maximise the anti-tumour activity of CD4+ T cells," Quezada added.

Work is now underway in our lab to develop new personalised cell therapies where the activity of Blimp-1 can be maxed up to drive potent tumour control, the researchers said.

According to the study, T cells are a subset of lymphocytes (white blood cells), which play a key role in the body's immune response. In immunotherapy T cells are modified and used to attack cancer.

These cells move around our bodies, looking for infected cells and killing them.

However, T cells do not recognise most cancers, since cancers develop from our own tissues and appear normal to most T cells, the research said.

The main challenge with T cell immunotherapy approaches is to find ways to direct T cells to attack cancer cells.

"Cellular therapies have only recently entered the mainstream in terms of clinical application. Our findings broaden our understanding of the regulators of T cell differentiation, illuminating new elements that might be targeted to enhance therapeutic efficacy," said study researcher Karl Peggs from the University College London in UK.

According to the researchers, the study like this helps scientists understand better the intricacies of our immune system and how it can be utilised to kill cancer cells.