Evaluating cytokines in immunotoxicity testing

One of the most potentially useful tools in immunotoxicology is the assessment of cytokines, the proteins/peptides that are responsible for regulating a variety of processes including immunity, inflammation, apoptosis, and hematopoiesis. Cytokine production measurements offer an outstanding promise and may eventually substitute for other more laborious procedures. The particular profile of cytokine production may provide an important information regarding the nature of many immunotoxic responses. Recent expansion in the knowledge of cytokine biology and the realization that cytokines play a role in human diseases have created a need for the precise assessment and accurate interpretation of their presence and activity in the body fluids, tissues and cells. Proper evaluation of cytokines requires attention to several technical details. Multi-cytokine analysis still needs to be standardized in terms of optimum source for analysis, protocols and quality control issues, such as the use of reference standards and the expression of results. Important practical details and considerations will be discussed in this chapter, including the source of the sample to be tested (circulating fluids, or ex vivo/in vitro isolated cells), the potential effects of collection, processing, and storage of the results of the assays, as well as potential variables associated with the source material (matrix effects, relevance, inhibitory substances), and factors influencing the choice of assay used (bioassay, immunoassay, molecular biology technique, flow cytometry).