Assessment of specificity of antisera for immunohistochemistry.

Publisher Website
Google Scholar
Abstract
The problem of specificity of antisera is one of the most important points in immunohistochemistry as well as in radioimmunoassay (RIA). However, the evaluation about specificity required in these two methods are quite different. In immunohistochemical staining, antisera which can never be used in RIA have been successfully employed. For example, anti-hCG was used for staining rat pituitary LH cells, and anti-mammalian LHRH was used for staining avian hypothalamus. On the other hand, very useful antisera for RIA are often eliminated in immunohistochemistry because of poor specificity. Such different evaluation is understandable if we compare the principles of these methods. The principle of RIA is the competitive binding, while immunohistochemistry based on the non-competitive binding where substances with very low affinities to the antibody can be bound if the concentration of antibody is satisfactorily high. In immunohistochemistry, the coexistence of antibodies to substances other than target antigen is very significant, while in RIA only the crossreactivity is important, and the competitive binding test gives no information about that. So, the evaluation of the antiserum in immunohistochemistry should be carried out using the non-competitive binding test which is based on the same principle to that of immunohistochemistry, and the results should be compared with those obtained with the competitive binding test which gives important information about the difference of the affinity constants of crossreacting substances.