[Spontaneous aortic lesions in the rabbit. Possible role of immune mechanisms]

The incidence of spontaneous arteriosclerosis, studied in 493 rabbits, increased with ageing. Various evidences suggested the immune nature of these lesions : 1. The direct immunoperoxidase test showed the binding of both rabbit IgG and complement on injured areas, while in apparently normal structures of the same aortas (endothelium and elastic fibers) this binding occurred in some areas with only IgG. 2. The indirect immunoperoxidase test demonstrated the binding of the gammaglobulins from rabbits with spontaneous arteriosclerosis to the aortic structures of normal young rabbits (myocytes, endothelial cells and elastic fibers). The previous demonstration of a cross-antigenicity between aortic glycoproteins and E. coli lipolysaccharides on the one hand, the positivity of delayed hypersensitivity reactions against E. coli lipopolysaccharides in rabbits with spontaneous aortic lesions on the other, led to the hypothesis that lipopolysaccharides antibodies might both bind and injury some aortic structures.