Genetically modified pigs – donors of the future

The idea of using the organs of genetically modified pigs for transplantation to humans is not new, but so far the efforts of researchers have been aimed at gradually, one at a time, introducing complement inhibitor genes into the chromosomes of pig cells – proteins that stop the launch of the so–called complement cascade - an acute inflammatory reaction leading to rejection of transplanted organs, even human, but not coinciding with the recipient in proteins of the main histocompatibility complex.

Researchers at Shanghai Jiaotong University, working under the leadership of Kuang-Yen Chou, approached the problem from the other side.

Complement inhibitors are proteins specific to endothelial cells lining the inner surface of blood vessels. Chinese scientists conducted experiments using two lines of pig vascular endothelium cells. Genetically modified cells of the same line expressed the human PD-L1 gene encoding the human ligand of programmed cell death-1. The second line of unchanged cells acted as a control. When culturing cells with human lymphocytes – immune cells that cause the development of a transplant rejection reaction – the modified cells caused significantly less pronounced activation of lymphocytes than the cells of the control line.

These results indicate that the human protein PD-L1 can be used as a means to increase the tolerance of the body to xenogenic (belonging to an organism of another species) transplants. Another possible variant of this approach is the use of genetically modified pigs expressing the human PD-L1 gene as donors.

Article by Qing Ding et al. Human PD-L1-overexpressing porcine vascular endothelial cells induce functionally suppressive human CD4+CD25hiFoxp3+ Treg cells is published in the July issue of the Journal of Leukocyte Biology.

Evgeniya Ryabtseva
Portal "Eternal youth" www.vechnayamolodost.ru Based on ScienceDaily: Genetic Alterations in Pig Tissue May Allow for Human Transplantation.

04.07.2011