Scientists have developed the first vaccine—tested so far only on animals—that clears away a brain protein that accumulates in some cases of Parkinson’s disease.As yet, only mice bred to develop the same plaque deposits seen in humans, have been tested. About 30 to 40 per cent of the mice responded to the vaccine. Of those, 50 per cent had less damage than mice with no exposure to the treatment.Dale Schenk, chief scientific officer at Elan Pharmaceuticals in South San Francisco, teamed up with Eliezer Masliah of the University of California, San Diego, to develop the vaccine. Schenk’s group also developed an experimental vaccine for Alzheimer’s that used an abnormal protein, beta amyloid, which caused the immune system to make antibodies that reduced levels of the abnormal protein in the brain. When the Alzheimer’s vaccine was tested on humans, however, 18 of 300 patients developed brain swelling and the trial was halted. Investigators have started new tests using a new procedure, bypassing the immune system.The Parkinson’s story may be more complicated because the disease involves many abnormal proteins that can damage cells. Several Parkinson’s genes have been discovered. One gene makes a protein called alpha-synuclein, which accumulates as plaque in the brain. Schenk and his colleagues delivered a vaccine that contains a small amount of the alpha-synuclein protein and found that the body waged an antibody response against it. ‘‘It has long-term implications for Parkinson’s patients,’’ Schenk said. —LATWP
