The immune system is a collection of billions of cells that travel through the bloodstream. They move in and out of tissues and organs, defending the body against foreign bodies (antigens), such as bacteria, viruses and cancerous cells.There are two types of lymphocytes :B cells-produce antibodies which are released into the fluid surrounding the bodyâs cells to destroy the invading viruses and bacteria. T cells (see picture opposite) - if the invader gets inside a cell, these (T cells) lock on to the infected cell, multiply and destroy it.here are two types of lymphocytes : B cells-produce antibodies which are released into the fluid surrounding the bodyâs cells to destroy the invading viruses and bacteria. T cells (see picture opposite) - if the invader gets inside a cell, these (T cells) lock on to the infected cell, multiply and destroy it.
Gillespieâs algorithm (Gillespie, 1977) is a way of im-. plementing consistently this probabilistic description of a biological system. The probabilistic. description by its very nature applies to single cells. The connection with molecular concentra-.
The concept of algorithm has existed for centuries, however a partial formalization of what would become the modern algorithm began with attempts to solve the Entscheidungsproblem (the decision problem) posed by David Hilbert in 1928. prototypical example of an algorithm is Euclid's algorithm to determine the maximum common divisor of two integers; an example (there are others) is described by the flow chart above and as an example in a later section. Boolos & Jeffrey (1974, 1999) offer an informal meaning of the word in the following quotation: