Lymphoid tissue architecture and pathological influences of toxicants
bookPart
The discipline of pathology plays a crucial role in the process of identifying and defining the health effects of exposure to compounds. The characterization of morphological alterations of laboratory animals after exposure is a significant step in this process. Histology of lymphoid organs has been found quite sensitive in a number of studies, including interlaboratory validation studies, although it did not flag every model immunotoxic substance. This is related to two aspects. First, the immune system by its very dynamic nature manifest a bandwidth in its morphological picture, hence the 'normal' state can be quite variable. Second, more subtle interferences of toxic compounds, for example, in cell traffic, specific actions on cell subsets with a distinct function, transmembrane signaling, and cell activation are often not detectable by conventional histological assessments. In the interpretation of quantitative changes, it should be noted that particular components of the lymphoid organs may be decreased in number (suppressed-involuted) or increased (stimulated-expanded), but that does not necessarily reflect the overall effects on the immune system. For proper hazard identification, interspecies- and intrastrain-dependent differences in the histophysiology of lymphoid organs should be taken into account, as well as the functional and morphological changes in lymphoid organs during life. The high sensitivity at perinatal age for a number of immunotoxicants has received specific attention in immunotoxicity testing.The chapter addresses the histology of lymphoid organs, including briefly tertiary lymphoid structures. Toxicant-induced pathologies are presented and associated mechanisms of toxicity are discussed
TNO Identifier
461964
Publisher
Pergamon
Article nr.
Chapter 8
Source title
Toxicology of the Immune System
Editor(s)
Lawrence, D.C.
Pages
171-190
Files
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