Objective  To establish a platform to monitor the immune rejection after abdominal aortic patch suture in a xenotransplantation model.

  Methods  The carotid was excised from wild-type Guangxi Bama pigs, cut into 2.5 cm × 1.0 cm pieces in shuttle shape and subsequently sutured to the abdominal aorta of cynomolgus monkeys. No immunosuppressive agent was administered. General conditions of the recipient monkeys were observed. The morphological changes of the graft artery were assessed by pathological examination at postoperative 1 year. Before and 7, 14, 28 and 49 d after surgery, the blood samples were collected from the recipient monkeys. The serum levels of IgM and IgG antibodies were quantitatively measured by the red blood cell and peripheral blood mononuclear cell (PBMC) from Guangxi Bama pigs. The quantity of lymphocytes in the recipient monkeys was detected by routine blood test and flow cytometry.

  Results  All 3 monkeys undergoing transplantation survived well. At postoperative 1 year, the lateral tissues of the vascular wall at the artery graft were seen in dark red color. Hematoxylin-eosin (HE) staining revealed a large quantity of red blood cell and platelet deposition, accompanied with lymphocyte infiltration. Using porcine red blood cell and PBMC as target cells, the serum levels of anti-pig IgM and IgG antibodies peaked at postoperative 28 d, and slightly declined at postoperative 49 d. The quantity of lymphocytes and T cell subset also peaked at postoperative 28 d and began to decrease at postoperative 49 d.

  Conclusions  Artery patch suture is a simple and reliable xenotransplantation model. The recipients can maintain normal physiological state without the use of immunosuppressive agents. The grafts can effectively activate the immune system of the recipients, induce the production of anti-pig antibodies and provoke cellular immune rejection. Therefore, this model can be utilized to monitor the immune rejection throughout the xenotransplantation process.