Enzyme immunoassays (EIAs) of eicosanoids

Enzyme immunoassay of eicosanoids is a nonradioactive, highly sensitive method of determining the concentration of eicosanoids in biological samples. Although relatively easy to use, the assays require a high level of precise pipetting technique and familiarity with critical points in the assay procedure. Although assay kits complete with plates, buffers, antibodies, tracers, and color development reagents are available, it is more economical to develop the assay within the laboratory if the assay is to be performed routinely. The only major disadvantage with EIA is that the investigator is limited to measuring eicosanoids with commercially available enzyme-tracers and antibodies. The labeling of particular eicosanoids by enzyme tracers is rarely, if ever, performed outside of industry. Growing of antibodies is conducted in many laboratories but is beyond the scope of this chapter. It requires a significant level of commitment of time and resources to establish the specificity of the antibody (i.e., does the antibody cross-react with eicosanoids of similar structure). Furthermore, this will not solve the problem of availability of eicosanoid-tracer. On the other hand, it must be noted that with the exception of the cytochrome P-450 metabolites of arachidonic acid, most of the major eicosanoids that are biologically active and are known to play regulatory roles in physiology and/or pathology, have commercially available antibodies and enzyme-tracers.