Turned on by Danger: Programme Notes
Dr Polly Matzinger is a sheep-dog trainer, former bunny girl,
and one of the world's foremost immunologists. Four years ago
she had a blinding moment of insight that led to a most extraordinary
idea, the Danger Model. This film tells the story of how a high
school drop out became a scientist, and had an idea that's reshaping
the way people think about organ transplants and cancer.
Polly Matzinger left school under the cloud of being voted by
her fellow students, "the person least likely to succeed in life".
She spent ten years drifting, as a jazz musician, a dog trainer,
and then a Playboy bunny. One evening she was serving drinks to
a couple of scientists who were discussing their experiments.
She asked a few incisive questions. One of the scientists was
so impressed that he started a nine-month campaign to persuade
her to go back to school to do science. Twenty years later she
is chief of an immunology lab at one of America's leading research
centres, the National Institutes of Health in Washington, and
the main proponent of a radical theory.
For half a century doctors have been taught that the body's immune
system attacks anything that's foreign. Not so, says Polly. The
idea that the immune system operates like a rampaging skinhead,
indiscriminately attacking foreigners, does not explain how we
tolerate the millions of "good" bacteria that colonise our gut,
nor does it explain why pregnant women do not reject their "foreign"
babies. Instead, Polly Matzinger argues that the body will attack
anything that attacks it. Our immune system responds, not to foreigness,
but to danger.
Her theory points the way to a revolution in transplant surgery:
it suggests ways of doing transplants without the fear of rejection
and the need for immunosuppressive drugs. Horizon has filmed something
that has never been done before: a mouse with a transplanted rat's
heart inside him. Such transplants are so foreign they should
be immediately rejected. Yet this mouse, on no drugs and with
a completely normal immune system, has accepted the rat's heart
as part of himself. Her "Danger Model" has also inspired novel
cancer therapies; 32 year old Briton, Geoffrey Allen, has advanced
cancer that has spread to his bones. At one of London's leading
teaching hospitals he is being injected with bacteria in the hope
that this will trigger a danger response, arousing his immune
system to attack his cancer. And it does appear to be responding.
Her assault on long established beliefs has provoked a passionate
debate. Polly Matzinger tells the moving story of her own, very
unusual life and the extraordinary moment when it all came together.