Trying everything they could in mice to tweak the immune system, Krummel and Allison soon found that a protein receptor called CTLA-4 seemed to be holding T cells back, like a brake in a vehicle.
Releasing the potential of immune cells to attack cancers joins other treatments including surgery, radiation and drugs.
One of Carter's treatments was a drug that blocked the immune-cell "brake" studied by Honjo.
The institute added that therapies based on Prof Honjo's discovery "proved to be strikingly effective in the fight against cancer". Allison, a professor at The University of Texas M.D. Anderson Cancer Center in Houston, discovered that a molecule called CTLA-4 (cytotoxic T-lymphocyte antigen 4) acts as a "brake" on the immune system; remove the brake and-in many cases-immune cells are unleashed to fight the cancer. "I didn't set out to study cancer, but to understand the biology of T cells, these incredible cells that travel our bodies and work to protect us", he said. The recipients include K. Barry Sharpless, who won he Nobel in chemistry in 2001 for his insights on antibodies, and Bruce Beutler, who won the prize in physiology and medicine in 2011 for his work in immunology.
Thanks to Allison's doggedness, anti-CTLA-4 therapy is now an accepted therapy for cancer and it opened the floodgates for a slew of new immunotherapies, Krummel said. Honojo's lab discovered when they injected antibodies against PD-1 that cancer cells could no longer dupe the T-cells.
For decades researchers had been trying to figure out effective ways to use the body's own immune system against cancer. Allison's initial findings can be credited for prompting researchers, including Allison himself, to carry out the studies that have demonstrated the potent anti-cancer effects of PD-1 antibodies.
The 70 year-old Allison worked as a postdoctoral fellow at Scripps Research from 1974-77, when the center was known as the Scripps Clinic and Research Foundation.
Lanier, who like Allison is a center director for the Parker Institute for Cancer Immunotherapy, says he is thrilled that such basic research was recognized.
The Nobel Assembly in Stockholm said the therapy "has now revolutionised cancer treatment and has fundamentally changed the way we view how cancer can be managed".
Allison said in a statement early Monday, "I'm honored and humbled to receive this prestigious recognition".
"We need these drugs to work for more people", Allison said.
In 2016, after being treated with a drug inspired by Prof Honjo's research, he announced that he no longer needed treatment.
"Until the seminal discoveries by the two laureates, progress into clinical development was modest".
Medicine is the first of the Nobel Prizes awarded each year.
Meanwhile, the fact that the literature prize will not be handed over this year has grabbed several headlines.