MODEL RELEASED. Immunodeficiency research. Dr Don Mosier counts mouse and human cells in a SCID (severe combined immunodeficiency) mouse that he implanted with a human immune system. The device at right is a fluorescence-activated cell sorter. The rare genetic mutation of SCID, found in both mice and humans, destroys the immune system and the body is unable to fight infection. Dr Mosier managed to implant disease-fighting human white blood cells into SCID mice giving them a permanent human immune system. This breakthrough enables researchers at the Scripps Research Institute in California, USA, to study human immune disorders such as SCID, AIDS, leukemia and allergies. MODEL RELEASED.