Immuno-electron microscopical features of in vivo antibody binding during pemphigus blister formation. Revelation with a new technique: peroxidase-labeled protein A.

Pemphigus autoantibodies, bound in the epidermis during different stages of acantholysis, were demonstrated with a new technique for immuno-electron microscopy. Peroxidase-labeled Protein A was used as a new and specific tracer for tissue-bound antibodies of the IgG-type. Advantages were: (1) A small molecular weight of the tracer, (2) a rapid tissue penetration, and (3) shortened incubation times, thus better preserved tissue fine structures. Unspecific adsorption in tissues and on cells was found to be comparatively low.