Quality control of antibodies with special reference to prostaglandins

Sources of error in the immunoassay of prostaglandins are reviewed. First, the specificity of the antibody, in terms of cross-reactions with structurally related substances, is often tested against irrelevant compounds, i.e. available compounds that do not occur in the biological material under study; major metabolises occurring in much larger amounts are overlooked. Hence, the reported high specificity of some antibodies may be apparent only. Second, many eicosanoids occur in two or more chemical forms in equilibrium in aqueous media. Antibodies may recognize one form preferentially; thus comparison of data from different laboratories is difficult. In addition numerous factors may interfere with the antigen-antibody binding in a non-immunological way. The most common effect is inhibition of antigen-antibody binding, but enhancement of binding sometimes occurs.