Immunology is a branch of biomedical science that covers the study of all aspects of the immune system in all organisms.[1] It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities, immune deficiency, transplant rejection); the physical, chemical and physiological characteristics of the components of
Immunology is the branch of biomedical science that deals with the response of an organism to antigenic challenge and its recognition of what is self and what is not. It deals with the defence mechanisms including all physical, chemical and biological properties of the organism that help it to combat its susceptibility to foreign organisms, material, etc.
Innate and adaptive immune systems
The immune system is divided into those which are static, or innate to the organism, and those which are responsive, or adaptive to a potential pathogen or foreign substance.
The innate system of immunity is on evolutionary terms, the older system that forms the first line of defence. It is non-specific and the resistance is static (it does not improve with repeated exposure and there is no memory on subsequent exposures). This includes physical defences such as skin & epithelial surfaces, cilia, commensual flora, acidic gastric contents, fever etc. Others are biochemical defences such as soluble - lysosyme, acute phase reactants and complement, fibronectin, interferons. Cellular components include natural killer cells, RES phagocytes.