Arteries from animal sources are readily available which possess physical properties similar to those of human arteries. If chemical or antigenic modification allowed their successful use in man, the difficulties attending the procurement of adequate numbers of normal human arteries for use as grafts would be alleviated. This study is concerned with methods of changing the antigens of equine arterial tissue by partial peptic digestion and the immune response in the dog and man following implantation of equine carotid arteries modified by partial proteolysis. Experiences with these grafts in 16 subjects and the immunologic reactions produced in them form the basis of this report.
A method of altering the antigens of the equine arterial wall has been previously described.3 Three-hour digestions of filtrates of horse carotid artery homogenates with a suspension of 0.1% crystalline pepsin in acid buffer at 37 C was found to abolish complement fixation