The status of chimeric cells in a human to pig spleen transplantation model
Introduction A human-to-pig spleen transplantation model was established at our lab to mimic the real immuno-reaction of human-anti-pig grafts in vivo. The status of chimeric cells was investigated in this model.
Materials and methods Castrated male Neijiang pigs (1-2 years old, 60-90 kg, n = 5) were immuno-suppressed by cell mediated lympholysis (CML) test. Human spleen slices were transplanted into pig peritoneal cavity 4 days later. The pig's peripheral blood were sampled for human against pig and pig against human cytotoxicity monitoring by CML as well as the chimeric level monitoring by flowcytometer (FCM) before operation, the operation day and different time of postoperation.
Results (1) The pig's peripheral blood white blood cells (PBWBC) was decreased to 15% of normal level on the operation day. (2) The chimeric peaks were observed on day 2 and day 14 postoperation at the chimeric rate of 6% and 3%, respectively. (3) The cytotoxicity of pig against human was increased to 50% within 1-2 weeks and decreased to 30% at 4 weeks postoperation. While the cytotoxicity of human against pig increased from 10% to 18% at 2 weeks after operation and less than 10% after 4 weeks.
Conclusion (1) The chimeric cells could formed two peaks on day 1 and day 14 after operation. (2) During the second peak periods, it might cause the highest cytotoxicity of human against pig as well as the highest CML of pig against human. (3) The result suggested that there might be a dynamic changeable balance of HVG, microchimerism and GVH caused by chimeric human cells and pig cells on human to pig spleen transplantation model.