"We utilized a laboratory model to simulate PERV (porcine endogenous retrovirus) transmission by infecting human cells with the virus," said Dr Clive Patience, Director of the Safety Program at Immerge. "We found that human retrovirus elements were not detectable in the PERV particles released from the infected human cells. These results are encouraging, as we used very sensitive assays that can detect 1 out of 50,000 to 1 out of 10 million elements. Therefore, if human cells were ever to become infected by PERV, the likelihood of porcine and human viruses recombining to form a novel infectious virus is extremely remote."
PERV is a natural virus in pigs, but does not cause any disease in these animals. In certain laboratory conditions PERV can infect cells from other species, including some human cells. However, there are no indications that PERV infection has occurred in living individuals, including humans that have been treated with pig tissues or those that are in regular direct contact with living pig cells or tissues.
"The risk of cross-species spread of PERV should be balanced by the potential efficacy of the transplanted tissue," commented Dr Julia Greenstein, CEO of Immerge. "Our progress in safety research continues to show that this risk can be addressed. We have previously identified animals within our miniature swine herd that do not transmit PERV to human cells; these new data show that even if this were to occur, it is highly unlikely that recombination with human viruses would result."
There is a critical need to identify new sources of organs for the growing number of people needing life-saving transplants around the world. In the U.S. alone, there are more than 81,000 people on the waiting list for organs and an unknown number of additional people needing organs who did not qualify for the transplant list because of age, illness or other issues.
As part of its progress toward clinical xenotransplantation, Immerge BioTherapeutics Inc. has developed a safety program with a number of international expert collaborators. The depth of Immerge's safety program is unique among companies conducting xenotransplantation research. The company has previously reported the first identification of receptors for PERV (Ericsson et al., Proceedings of the National Academy of Sciences 2003; 100: 6759-6764). In the past year, in collaborative efforts with the University of Missouri-Columbia and Infigen, Inc., Immerge also announced the birth of cloned, double knock-out miniature swine that lack expression of the GGTA1 gene. This gene is responsible for rapid rejection of organs and makes the animal organs more compatible for potential human transplant.
Immerge BioTherapeutics was formed on September 26, 2000, as a joint venture between Novartis Pharma AG and BioTransplant Incorporated. The company, which began operations on January 2, 2001, focuses its research efforts toward developing therapeutic applications for xenotransplantation.
Journal
Virology