MORPHOLOGY AND DISTRIBUTION OF IMMUNE DEPOSITS IN THE SKIN. THE ACTIVE ARTHUS REACTION USING HORSERADISH PEROXIDASE AS ANTIGEN*
A model of the active Arthus reaction was studied immunohistochemically in the skin using a horseradish proxidase-anti peroxidase system, comparing with the results of the reversed passive Arthus reaction in the skin of rabbits. Fine or coarse granular deposits and lumpy aggregates of peroxidase-positive substances are considered to represent immune deposits, while the homogeneous staining of peroxidase may show the nonreacted free peroxidase. In the present study it was found that immune complexes precipitate not only on the vascular walls, but also widely in the skin, i.e., along the collagen fibers, in the dermo-epidermal junction and in the perifollicular areas in the active Arthus reaction, and that they adhere to the surfaces of histiocytes, polymorphonuclear leukocytes, fibroblast-like cells and also of epidermal cells.