Replacing An Immune System
An impressive demonstration is noted at EurekAlert!: researchers "have successfully used adult stem cells to replace the immune system and bone marrow of mice ... The researchers used multipotent adult progenitor cells (MAPCs), which can be isolated from bone marrow ... Verfaillie and her team isolated MAPCs from mice and expanded them for at least 80 doublings in the lab. They then transplanted the cells into mice that received radiation and thus had no immune system. ... The cells not only survived when transplanted but they completely repopulated the blood system of the mice." Is there a near-term path here towards a viable, safe methodology for replacing an age-damaged and ineffective immune system? Perhaps not, unless another methodology could be used to remove the original system: "Scientists must now understand that mouse MAPCs can make normal blood, and we need to explore how they do it. It is very important to note that MAPCs were not themselves radioprotective, thus they alone could not be used in patients in whom the bone marrow is totally eliminated due to radiation or chemotherapy, but it is still remarkable that they can give rise to blood cells."
Link: http://www.eurekalert.org/pub_releases/2007-01/uom-uom011207.php