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 non-self. It deals with the defense mechanisms including all physical, chemical and biological properties of the organism that help it to combat its susceptibility to foreign organisms, material, etc. Immunology deals with physiological functioning of the immune system in both health and disease state as well as malfunctions of the immune system in immunological disorders. Immunology deals with physical, chemical and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo. Immunology has a vast array of uses in several disciplines of science and medical science.