Immune System May Reject Stem Cells
Reported August 20, 2008
(Ivanhoe Newswire) — New research strikes down the idea that the immune system is blind to the presence of foreign embryonic stem cells.
Researchers at the Stanford University School of Medicine recently found the immune systems of mice rejected human embryonic stem cells.
Scientists watched the progress of the injected cells using a new real-time molecular imaging technique. The cells died in mice with normal immune systems within about seven to ten days but survived and multiplied in mice with weakened immune systems.
The data is quite convincing, Joseph Wu, M.D., Ph.D., assistant professor of cardiovascular medicine and radiology at the Stanford University School of Medicine, was quoted as saying. Based on these results, we believe that transplanting these cells into humans would also cause an immune response.
Since the mices reactions were similar to the way humans react to transplanted organs, researchers investigated whether anti-rejection medications would increase stem cell survival. They found a combination of tacrolimus (Prograf) and sirolimus (Rapamune) kept the cells alive for up to 28 days in mice with normal immune systems.
SOURCE: Proceedings of the National Academy of Sciences, published online Aug. 18, 2008