Comparative immunologic models can enhance analyses of environmental immunotoxicity

To treat immune systems and how environments affect them is a unique challenge especially when the environment is considered in its broadest perspective: internal and external. Internal focuses on relationships between immune, nervous and endocrine systems (neuroendocrine) and how they interact to maintain homeostasis. External considers physical and chemical influences that act to change the internal. Using animal models is based upon phylogeny which focuses on invertebrates, fish, amphibians, and reptiles, including mammalian results and relationships to humans. Emphasizing primitive animals is due to a growing interest in using them as models, sentinels, surrogates—predictors of what may happen when the environment is disturbed. They are inexpensive, socially acceptable, and since they live in diverse habitats under natural conditions, what may happen to them may be more applicable to humans than to laboratory reared models (sometimes inbred) whose controlled habitats may not be considered as natural. Humans do not live in controlled laboratories but like numerous animals, we do live in various climates, under different conditions of light, temperature, crowding, seasons and in different habitats that determine the quality of life including the susceptibility to disease. The immune system is affected by these influences, and it in turn is responsible for the body's surveillance against these threats.