ABSTRACT
Immunity can be classified as non-specific and specific. Both types depend on the immune system's ability to distinguish between self-and non-self-molecules. The non-specific immune system does not recognise the substance that is being attacked, but responds against pathogens in a generic way, and does not confer long-lasting immunity against pathogens. Specific immunity is antigen specific and requires the recognition of non-self-antigens during a process called antigen presentation. It confers immunological memory by the action of memory cells. This allows for a stronger immune response that confers immunological memory for specific pathogens. The major components of specific immunity include T and B lymphocytes, plasma cells, antibodies, the classic complement pathway, and immunological memory. B lymphocytes are involved in humoral immunity and T lymphocytes in cell-mediated immunity. Hypersensitivity reactions are abnormal immune responses, including allergies and autoimmunity, that damage the body’s own tissues.
