Production, characterization, and use of serpin antibodies.

Serine protease inhibitors (serpins) constitute a still expanding superfamily of structural similar proteins, which are localized extracellularly and intracellularly. Serpins play a central role in the regulation of a wide variety of (patho) physiological processes including coagulation, fibrinolysis, inflammation, development, tumor invasion, and apoptosis. Serpins have a unique mechanism of inhibition that involves a profound change in conformational state upon interaction with their protease. This conformational change enables the production of monoclonal antibodies specific for native, complexed, and inactivated serpins. Antibodies, and assays based on these antibodies, have been helpful in elucidating the (patho) physiological function of serpins in the last decade. Serpin-specific antibodies can be used for: (1) structure-function studies such as detection of conformational changes; (2) identification of target-proteases; (3) the detection and quantification of serpin and serpin-protease complexes in bodily fluids by immunoassays such as ELISA, RIA or FACS; (4) detection of serpins in tissues by immunohistochemistry; and (5) possible therapeutical interventions. This review summarizes the techniques we have used to obtain and screen antibodies against extra- and intracellular serpins, as well as the use of these antibodies for some of the above-mentioned purposes