Loss of Galα1-3Gal and vWF from porcine xenografts. Tissues from porcine pulmonary, renal, and cardiac xenografts were assayed for reactivity with GSL I-B4, a lectin specific for Galα1-3Gal, and mouse anti-porcine vWF. A: Porcine pulmonary tissues taken 15 minutes after transplantation into baboons have markedly less vWF and less reactivity with GSL I-B4 than porcine pulmonary tissues taken before transplantation (0 minutes). Original magnification, ×400. B: Porcine renal tissues taken 60 minutes after transplantation into baboons have less vWF but only focal or no decrease of Galα1-3Gal based on reactivity with GSL I-B4 than porcine renal tissues taken before transplantation (0 minutes). Original magnification, ×400. C: Porcine cardiac tissues taken 60 minutes after transplantation into baboons have less vWF but only focal or no decrease of Galα1-3Gal based on reactivity with GSL I-B4 than porcine cardiac tissues taken before transplantation (0 minutes). Original magnification, ×400.