Chapter 3 : Application of Ganoderma in Immune Modulation. Page 49. Introduction to the immune system . How the human immune system works. The human immune system is very complicated as it is a precise biochemical system composed of different types of immune cells that interact in a cooperative yet restrictive , way to protect the body . Once the system is impaired immunity is reduced or lost, allowing foreign bodies to invade , eventually leading to sickness or death. Immune cells include : phagocytes ( including macrophages, dendritic cells , neutrophils, etc), natural killer cells, T cells , B cells etc. During cell development, T cells develop into Th1 and Th2 cells ; B cells are responsible for producing antibodies. Immunologists call these immune cells, which are diversified in nature, leukocytes or white blood cells. Normally these are betweem 3,500 to 9000 white blood cells in a micro-liter of blood in a healthy person .When the white blood cells count falls under 30
