Immunotherapy to treat cancer gets Nobel boost Immunologists, Honjo and Allison win Nobel Medicine
James Allison of the US and Dr Tasuku Honjo of Japan have won the Nobel Prize for Medicine for 2018. All along treatment for cancer meant external interventions from chemotherapy to radiation to surgery. Now the work of these two scientists, working separately which started off in the 1990s, showed how it is possible to stimulate the body’s own immune system to attack cancer. They have proved how certain proteins act as “brake” on the immune system’s T-cells, limiting their ability to attack cancer cells. T-cells are a type of white blood cells that can identify and kill infected, damaged or cancerous cells, using their claw like receptors that can recognise and lock on to antigens – foreign bodies on the surface of infected or cancer cells. However, their capability is compromised when cancer cells avoid destruction by shutting down a switch on the T-cell called as an immune check point. This allows the cancer to grow undisturbed.
In 1995 Allison identified a protein, the CTLA-4 molecule that acts as an inhibitory receptor on T-cells and realised the potential of releasing this inhibitory brake and thereby unleashing our immune cells to attack tumours.
Around the same time, Honjo discovered a protein on immune cells, the ligand PD-1 and he too reaalised that this too acted as a brake on T-cells. Once these proteins that ‘brake’ the systems are removed or blocked, it frees the T-cell immune system to attack cancer cells. A single T-cell can kill thousands of cancer cells.
The work of these two scientists have led to new and dramatically improved therapies for cancers such as melanoma, lung cancer etc which are difficult to treat cancers.
The Nobel Assembly at Sweden’s Karolinska Institute remarked, “The seminal discoveries by the two scientists constitute a landmark in our fight against cancer. James P Allison, 70, is at present, Chairman of Immunology at the University of Texas MD Anderson Cancer Centre in the US. Professor TasukuHonjo, 76, is with the Kyoto University, Japan.
On the website of the Texas University, Allison wrote “It’s a great emotional privilege to meet cancer patients who have been successfully treated with im- mune checkpoint blockade. They are living proof of the power of basic science, of following our urge to learn and to understand how things work”.
The winners of the 2018 Nobel prize for Medicine: (L-R): Dr James Allison, Dr Tasuku Honjo