Louis Picker, associate director of the OHSU Vaccine and Gene Therapy Institute, created an experimental AIDS vaccine from cytomegalovirus, a virus that is just as persistent as HIV but doesn’t cause disease.
BY LINDA BAKER
To develop a vaccine, researchers typically identify the disease agent, weaken or kill it, then set it loose in the body. The immune system destroys the weakened virus, leaving the vaccinated individual with a host of immune cells to ward off future infection. Alas, that time-honored strategy doesn’t work with HIV; you can’t weaken the virus enough so it is still safe to dole out in vaccine form. HIV is also especially tricky to clear completely from the body. To get around these challenges, Louis Picker, associate director of the OHSU Vaccine and Gene Therapy Institute, created an experimental AIDS vaccine from cytomegalovirus, a virus that is just as persistent as HIV but doesn’t cause disease. In tests on 16 monkeys, the vaccine eliminated an aggressive form of HIV in half of them — the first ever to demonstrate that kind of success. “The standard vaccine generates a big [immune] response, but that response ultimately goes away,” Picker says. “Ours keeps the T-cells armed and ready all the time.” His team is now working to translate the vaccine into a form suitable for humans — and figure out why some of the monkeys were not protected. There are about 50 million HIV infections worldwide; none have been eradicated. With the new vaccine, Picker says, the odds are better. “The score is host 50, virus 50.”
