Switching the Bait

Screening for antibody biomarkers of disease to facilitate diagnosis has been fraught with failure, despite its logical approach: stick proteins onto a microscope slide and then pour over a patient's serum, full of disease-specific antibodies, and see what sticks. Compare the results to the serum of a healthy person, and you've got an antibody-protein pair that should signal disease. But of the proteins IDed employing that method, "none of them are even close" to clinical diagnosis, says Thomas Kodadek, at the Scripps Research Institute in Jupiter, Florida. Kodadek and his colleagues figured that the antibodies in the serum of an ill individual wouldn't be likely to bind to normal biological proteins. The immune system recognizes the foreign proteins of an invading pathogen or the markers of a dying cell precisely because they are different from the body's normal proteins. A cell involved in a disease like cancer or Alzheimer's is ...