Target organs and systems: methodologies to assess immune system function.

Immunotoxicity encompasses both reduced and heightened immune function. Diverse chemicals can impair functioning of the immune system. Both monographs and books have been devoted to detailed descriptions of immunotoxicity. This paper gives a brief overview of the methods currently used to assess the immunotoxic potential of chemicals. It also discusses the trend toward the use of alternative methods to mammalian models, such as feral species, in vitro assays, and computational models. The strategy of using a tier approach to screen chemicals for immunotoxicity is described, together with the rationale for, and limitations of, this approach. Interpretation of data with regard to clinical disease and human health is addressed. The immune system poses substantial complexities in this regard as the system has functional reserve and functional redundancy.