The immune system is a composite of the means by which individual organisms maintain their individual integrity in the face of constant interaction with the environment and the continuous internal process of death and removal of host cells that allows for replacement and growth. Both the innate and adaptive divisions of the immune system are critical to the maintenance of homeostasis, physical integrity, and health. Intricately interactive pathways of cells, cell surface receptors, antibodies, and cytokines provide surveillance against invasive pathogens and nonself entities and internal destruction and removal of host senescent cells. The specificity and efficacy of these immune components interacting with their respective ligands provide the mechanistic basis of immune function. Several disease conditions occur upon immune dysfunction including immune deficiency, allergy, and autoimmunity. Chronic immune system activation accompanies essentially all of the myriad of chronic inflammatory diseases that currently plague our species with the manner and degree of immune contribution to these conditions a current area of intense interest and investigation by the biomedical community.
Understanding the mechanisms by which the immune system works opens many possibilities for investigations within pharmacology. Objectives are principally three-fold: (a) to enhance function in the face of insufficient immune response, (b) to redirect immune processes that themselves may lead to host dysfunction, and (c) to exploit and/or attempt to mimic the exquisite specificity and mobilizing functions of immune responses in drug development.