Millions of potentially lethal cell mutations occur in each of us every day. We notice nothing; the immune system arrests and executes the offenders instantly. But with advancing age, its vigilance slackens. Mutations start to go unchecked; and we succumb to the melancholy neoplastic or degenerative diseases of old age.

So Daedalus is extending his scheme of last week for priming the immune system against all normal biological proteins. He now wants to prime it against abnormal proteins as well — in particular, the abnormal ones expressed on the surfaces of malfunctioning human cells. DREADCO volunteers are now providing small biopsy tissue samples of blood, lung, gut, and so on, to be cultured in the usual way. The cultures will then be attacked with mutagens, ultraviolet light, X-rays, and such, to induce as many mutations in them as possible. The battered and misfiring cells will express all sorts of crazy and altered proteins on their surfaces. These will be extracted, and injected back into the volunteer from whom the cells came. This ‘auto-immunization’ will prime his immune system against such cell mutations. Should a cell in his gut or liver start to go crazy in one of those pre-identified ways, the immune system will spot the abnormality at once. It will stamp on the rogue cell instantly.

Sadly, auto-immunization can never be a perfect defence. There are too many different body tissues, each with too many ways of going wrong, for any vaccine to contain all the proteins expressed by all these errors. But not all errors are equally likely, or equally deadly if they do occur. The human genome can suffer about 10 billion possible single-site mutations; yet there are only some 30,000 recognized illnesses of all kinds. The deadly diseases are those in which a mutated cell starts to multiply, or to trigger similar changes in its neighbours. So Daedalus will tune his treatment to his customers. If all your ancestors died of liver cancers, you'll include some liver cells in your tissue sample; if Dr Alzheimer stalks your family tree, you'll make sure that brain cells are well represented in it. And the mutagenic regime itself will be chosen to provoke the most appropriate type of cell damage. The resulting immunization will be an excellent defence against the disease of your fears. Sadly, it won't make you immortal. But you'll last much longer, and finally die of something you weren't expecting.