The present application relates to the use of a pertussis toxin, and its derivatives, analogs, salts and pharmaceutical equivalents. In one embodiment, the invention provides a method of treating an autoimmune disease by administering pertussis toxin to the individual. In another embodiment, the autoimmune disease is multiple sclerosis. In another embodiment, the invention provides a method of treating a neurodegenerative disease such as Alzheimer's disease or Parkinson's disease by administering pertussis toxin, or a derivative, analog, salt or pharmaceutical equivalent.
