How immunotherapy helps recognise and destroy cancer

Approach one

CTLA-4

Dendritic cell

T-cell

CTLA-4 protein

Dendritic cells, which help signal problems like cancer, bear molecules that the T-cell protein CTLA-4 normally recognise as an ‘off switch’

Jim Allison’s lab developed a drug which blocked CTLA-4, taking the brakes off the immune system and allowing the T-cell to attack cancer

Approach two

PD-L1

Cancer cell

Inhibitor drug

PD-L1

Cancer cells produce a molecule, PD-L1, which prevents T-cells from recognising them as a threat. Some drugs block the cancer’s ability to hide, allowing T-cells to destroy it

Approach one: CTLA-4

T-cell

Dendritic cell

Dendritic cells, which help signal problems like cancer, bear molecules that the T-cell protein CTLA-4 normally recognise as an ‘off switch’

CTLA-4 protein

Jim Allison’s lab developed a drug which blocked CTLA-4, taking the brakes off the immune system and allowing the T-cell to attack cancer

Antibody

Approach two: PD-L1

Cancer cell

Cancer cells produce a molecule, PD-L1, which prevents T-cells from recognising them as a threat. Some drugs block the cancer’s ability to hide, allowing T-cells to destroy it

Inhibitor drug

PD-L1