Laboratory Recognition of Potential Xenobiotic Respiratory Sensitizers

The immune system functions to establish and maintain homeostasis to protect the body from infectious agents and certain tumours. However, the interaction between the immune system and some xenobiotics can perturb this homeostasis, resulting in adverse health events, including the development of hypersensitivity reactions in genetically predisposed individuals. The dramatic increase in protein-induced respiratory hypersensitivity in the USA and other industrialized nations over the last few decades is presumably the result of changes in environment, lifestyle and/or medical practices. This chapter provides an overview of selected laboratory methods used in the identification and health-risk assessment of potential respiratory sensitizers. We describe animal models of hypersensitivity that have been used to elucidate disease pathogenesis and hazard identification. Methods for animal exposure, sample collection and end-point assessment are also discussed. In addition to in vivo models, the development of in vitro screening techniques and the utility of technologies such as protein and gene expression microarrays, PCR and multiplexing systems in hazard screening are also described. The models and methods discussed in this chapter have been used in our laboratory and others, not only to determine the risks associated with bioaerosol exposure, but also to elucidate disease mechanism and potential intervention targets. Keywords: hypersensitivity; allergy; hypersensitivity pneumonitis; animal models; cell culture