Generally speaking, the immune system works simply by comparing a potentially harmful critter against a large database of approved microscopic entities.
This has become the analogy du jour in explaining how a negative database works in software applications.
Last month, The Economist discussed this issue in “The non-denial of the non-self” stating,
The immune system is interesting, because it protects its owner from pathogens without needing to know what a pathogen will look like. Instead, it relies on a negative database to tell it what to destroy. It learns early on which biological molecules are “self�, in the sense that they are routine parts of the body it is protecting. Whenever it meets one that is “not self� and thus likely to be part of a pathogen, it destroys it.
And an academic research team led by Fernando Esponda and Paul Helman are trying to apply this nature-inspired, reverse psychology-esque system to secure sensitive information.
On a related note, Mercedes-Benz is developing a new car that is designed based on the streamlined features of a female boxfish. And while it may not be the sexiest looking vehicle on the road, gets about 70 miles/gallon.
See more on the dynamism of nature and engineering.
Via Mike Ewens.