Word: humanity
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Dates: during 1980-1989
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...pair of remarkable studies, one reported in the journal Nature and the other to be published in Science this week, researchers at the Medical Biology Institute in La Jolla, Calif., and at Stanford University, working separately and using different methods, successfully transplanted elements of the human immune system into mice. The achievement meant that such animals may soon serve as stand-ins for human beings in the study of AIDS and a host of other diseases, including leukemia and hepatitis. The mice could also be used to test drugs that would be unsafe to test in humans and to study...
...Stanford scientists announced their findings, which involved transplanting human fetal tissue into the mice, just as a special advisory committee of the National Institutes of Health was meeting in Bethesda, Md., to consider the scientific and ethical issues surrounding the use of human fetal tissue in experimental research. The reason: to develop recommendations that may influence the Reagan Administration's proposed ban on such federally funded research...
...work with fetal tissue was by far the more elaborate of the two research efforts. Led by Stanford's Dr. Mike McCune and Irving Weissman, the scientific team actually reconstituted a human immune system in mice that lacked their own immune systems. Because of a genetic abnormality known as SCID (for severe combined immunodeficiency), these mice usually die at an early age, often of pneumocystis pneumonia, the disease that kills many AIDS patients. The researchers implanted some 300 of the defective mice with tissue taken from human fetal thymus, where certain immune and blood cells develop, and with blood-forming...
After more than a year, the Stanford mice are still thriving. Their new immune systems, however, must be sustained by injections of fetal liver cells every eight to twelve weeks. In addition, researchers are not sure whether all the parts of the human system are functioning in the mice. "We'll find that out," says Weissman, "but we'll have to do every known test for human immune cells. These mice open ways of studying human systems, normal or diseased, under experimental circumstances that were impossible before...
...Jolla team also used SCID mice. By comparison, however, their approach was simple. Circulating white blood cells taken from human adults were injected into mice. Almost immediately, the mice began replicating the cells. Within three weeks they had human immune systems with nearly correct proportions of all the major types of white cells found in human blood. Moreover, when the researchers injected these mice with tetanus toxoid, most of the animals produced human antietanus antibodies, further proof that their new immune systems were functioning as though they were naturally human...