title: Comments on introducing the immune system.
abstract: It is argued that by studying some design principles of the immune system, e.g. nonlinearity and being a complex adaptive system, one can easily find some explanations of basic properties of the system e.g. memory and tolerance.
authors.affiliation: Mathematics department, Faculty of Science, Mansoura 35516, Egypt. magd45@yahoo.com.
authors.forename: E
authors.initials: E
authors.lastname: Ahmed