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-.
âThe theory of algorithms and a variety of computational models were developed.â âThe following year he wrote on number theory, making a contribution to the theory of the Euclidean algorithm.â âAll the algorithms to carry out arithmetical operations are presented in this way and no proofs are given.â