TABLE OF CONTENTS I have deliberately used this rather emotive description of this chapter's contents since, in order to survive and continue the process of replacing and renewing dead and dying cells, the body has had to develop a method of summoning up biological forces to defeat invasion from both outside and inside itself. Therefore, although we can use a variety of substances to repair damage to and within the body, we have to be aware that the reaction of the body to their introduction will be a hostile one. Therefore, to use materials as effectively as possible, we have to understand the nature of the body's defense system and how it works.
The study of the body's defense system (the immune reaction), began with Jenner's (1749-1823) work on smallpox in the late eighteenth century. Almost a hundred years later, it was discovered that the blood serum of animals that had been vaccinated (immunised) contained substances called "antibodies"; proteins (immunoglobulins) which attach themselves to foreign invaders, for example viral proteins (antigens), and are a vital component of the body's defense mechanism.
When the invading antigens appear, they are attacked by waves of antibodies, which combine with the antigens to neutralise them. The remaining white cells subsequently mature into cells called "macrophages", which embody the memory of the particular antigen, and become "hypersensitized". Should another invasion by the same species of antigen take place at a later date, these hypersensitized macrophages have the resources to manufacture very...
