New Form of
Michele Fizzano McFarland
A national group of researchers say vaccines can be designed
to suppress infection by the human immunodeficiency virus in
children--a twist from vaccines' normal role of preventing
A yearlong study of three similar, genetically engineered vaccines showed they were safe in symptom-free, HIV-infected children ranging in age from 1 month to 18 years. In addition, the vaccines affected the way infection-fighting cells handle the virus, giving researchers hope that further studies will prove vaccines can alter the spread of HIV in the body.
"They may keep the virus from actively replicating," John Lambert said. Lambert is an assistant professor of pediatrics and international health at Hopkins and study coordinator for a national group of researchers from the NIH-sponsored Pediatric AIDS Clinical Trials Group. "We are also anxious to learn if lab results will translate into healthier, longer lives for children," Lambert said.
Lambert presented the group's findings on May 7, at the 1996 meeting of the American Pediatric Society and Society for Pediatric Research in Washington, D.C.
HIV does its damage by attacking a certain type of T-lymphocytes called CD4 cells, which fight infection. The result is a weakened immune system, susceptible to life-threatening malignancies and opportunistic infections.
The recombinant envelope vaccines used in this study were manufactured in three different labs and made from plant proteins and bacteria. Becoming infected with HIV from one of the vaccines is impossible, since it contains no human by-products, Lambert said.
The vaccines contain a replica of HIV's outer shell, or envelope. In theory, the body recognizes the envelope as foreign and makes antibodies against it. Those antibodies not only go after the "impostor" virus, but the real one as well, protecting against HIV in two different ways. First, the antibodies block the ability of HIV to infect and kill T-lymphocytes. Second, they attack HIV floating in the bloodstream.
The study showed that all three vaccines succeeded in the first goal, proved by sampling cells after vaccine was administered at one-, two-, three-, four- and six-month intervals. Each time, the cells responded to a stimulus, indicating they "remembered" being helped by antibodies.
Future studies are needed to determine if enough antibodies are produced to fight HIV in the bloodstream, too, Lambert said.
All 79 volunteers remained healthy, with no evidence of severe reaction, adverse immune response, opportunistic infection or increased HIV replication.
However, Lambert warned, because all the children enrolled in the study were symptom-free, even the 21 patients who received placebo did not develop signs of worsening. "Thus, while this study shows us that therapeutic vaccination is safe in HIV-infected infants and children, we still don't know if the vaccines will give pediatric patients a better chance of survival in the long run," Lambert said.
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