Understanding the function and interaction of the molecular and cellular components comprising the immune system is the core definition of immunology. The vertebrate immune system is typically divided into two response systems, an innate or non-specific response immune system, and an acquired or adaptive immune system. Disorders in immune function can lead to diseases categorized under immunodeficiency or autoimmunity. Immunodeficient disorders are those that fail to provide an adequate response, and autoimmune responses are those that attack self (rheumatoid arthritis, lupus erythematosus). Still other disorders involve a hypersensitivity response, in which the system responds inappropriately to harmless compounds (asthma and allergies).
A dynamic and exciting area of immunology research involves examining the interactions of the immune system within the context of a tumor or malignancy. Immune responses, including the recognition of cancer-specific antigens, are of particular interest as the knowledge gained drives the development of new vaccines and antibody therapies.