The quest for an effective HIV vaccine has foiled scientists for years, in part because the virus comes in many everchanging forms. One solution may be to design a vaccine that produces sophisticated immune cells that can recognize many kinds of viruses.
New research at Los Alamos National Laboratory found that so-called mosaic vaccines produced immune cells in monkeys that can recognize many types of the HIV viruses that are circulating around the world.
The results offer hope for an effective, global vaccine for one of the world's most complex and deadly illnesses, said Bette Korber, a theoretical biologist at LANL and co-author of two new articles about the research.
"We're really hopeful about it," Korber said. "It's promising enough that the Gates Foundation and the NIH are investing in human trials to see if (the results) hold up in humans."
The studies were published in the online edition of the journal Nature Medicine.
Korber designed the vaccine that will be used in the human study, which could be completed in about five years. In the meantime, HIV viruses are likely to become ever more diverse, "but they change in characteristic ways that the mosaic vaccines cover pretty well," she said.
HIV, or human immunodeficiency virus, leads to AIDS, a disease that causes the immune system to fail. HIV is transmitted through bodily fluids such as blood and semen, often through sexual contact or blood transfusions.
About 33 million people worldwide live with HIV/AIDS, according to the World Health Organization. There is now no cure or vaccine for HIV.
LANL researchers in the 1980s created the world's first pathogenic database to store genetic sequences for HIV viruses from around the world. Today, the database holds about 10,000 different strains of the virus, Korber said.
To make the problem more vexing, the viruses can show enormous genetic variation. Virus taken from someone in New York can vary 15 percent from virus found in San Francisco, and 35 percent from that in Africa, she said.
Conventional vaccines work by injecting a person with dead virus, prompting the immune system to produce cells that can fight live forms of the same virus.
But the huge variety observed in HIV makes the targeted approach of conventional vaccines ineffective, Korber said. To solve the problem, she and her collaborators
make use of the fact that HIV consists of 10 proteins, each of which consists of a sequence of amino acids.
Those proteins vary widely from person to person, but all share certain key elements, she said. In making her vaccine, Korber used a computer to create several artificial proteins that can recognize a variety of circulating viruses.
The vaccine has the ability to read the amino acid sequence in HIV proteins, she said. The vaccines are called "mosaic vaccines" because they combine several artificial proteins to improve its ability to recognize many strains of HIV.