Manmade T Cells Aid The Assault On Aids

FOR AIDS AND OTHER CHRONIC DISEASES that attack the immune system, researchers have long hunted for a way to reinforce the body's defense mechanisms. But efforts to artificially create more of the disease-fighting T-cells found in the blood have fallen short: Not enough were created to do much good, and they soon lost their ability to target specific viruses and tumors. Now, immunologists at Fred Hutchinson Cancer Research Center in Seattle have figured out how to grow billions of highly specific T-cells in the lab and then use them to augment the immune system--an approach called adoptive immunotherapy.

Dr. Stanley R. Riddell and Dr. Philip D. Greenberg of Hutchinson call their technique the rapid-expansion method and have licensed it to Targeted Genetics Corp. in Seattle. They isolate a certain type of T-cell from a few tablespoons of a patient's blood and induce the cells to grow with the same chemical signals the immune system uses. In less than two weeks, the population multiplies into the billions, and when the T-cells are transfused back into the patient, they attack only diseased cells. Riddell says the manufactured T-cells seem to function just like their natural counterparts and remain active for at least three months. Although trials have yet to show whether this works better than current treatments for AIDS, it is "a promising advance that should make immunotherapy more feasible," says Dr. Peter C. Doherty of St. Jude's Children's Hospital in Memphis, a Nobel prize winner for his discoveries about the immune system.