Experimental arterial sensitization: Studies on the specificity of “shock tissue”

Abstract

1. 1. Albino rabbits of the same strain and approximate age and weight were passively sensitized with homologous antiserum to and challenged with horse serum according to a procedure favoring the production of acute lesions of vasculitis of the pulmonary arteries, arterioles, and veins. 2. 2. Of ten animals sensitized and challenged intravenously through the ear vein, all developed the typical lesions of periarterial infiltration consisting chiefly of eosinophils and polymorphonuclear leukocytes and, to a much lesser extent, lymphocytes and mononuclear cells with some eosinophilic infiltration into the adventitia, media, and intima of the small pulmonary arteries and arterioles. The vasculature of other organs was unaffected. 3. 3. Of nine animals subjected to similar procedures via the intracarotid arterial route, six developed similar pulmonary lesions, but the lesions were of milder intensity and were less frequently found than those sensitized and challenged by the intravenous route. The brains of these rabbits were free of lesions. 4. 4. Eight animals received similar sensitizing and challenging injections intraperitoneally. In this group, lesions suggesting pulmonary vasculitis were infrequently found and were of a very mild or equivocal degree. Lesions could not be demonstrated within the liver following this procedure. 5. 5. These results suggest that although modified by the route of administration of sensitizing and challenging doses, the development of acute lesions of pulmonary vasculitis may depend upon some undetermined specificity of the rabbit lung in participating in antigen-antibody reactions not found in the brain or liver of this animal. 6. 6. Although not apparent, the reason for the involvement of the pulmonary vasculature in this reaction, considered a tissue manifestation of subacute anaphylaxis, may be related to the role of the pulmonary arteries as “shock organ” in anaphylactic shock.