Some people make the body immune system proteins after infection with the AIDS virus, when the late difficult for them to do well. However well designed a vaccine that may help the body to produce it more quickly, the researchers reported in Friday editions of the journal Science.
"I am more optimistic about AIDS vaccine today than in the past 10 years," said Dr. Gary Nabel of the National Institute of Allergy and Infectious Diseases, who led the study, in a telephone interview.
Two of the antibodies can attach to and neutralize 90 percent of the various mutations of human immunodeficiency virus that causes AIDS, said Nabel.
"This is an antibody which develops after infection. That is part of our problem in dealing with HIV - once someone is infected, the virus is always leading from the immune system," Nabel said.
"What we are trying to do with the vaccine is one step ahead of the virus."
AIDS infects about 33 million people worldwide, according to UN AIDS agency. Aids has killed 25 million people since the epidemic began in the early 1980s and there is no vaccine or cure, although drugs can help control it.
Viruses are difficult to fight because of some immune system cells attack and partly to mutate constantly, making it a moving target for the drug or the immune system.
It's almost impossible to make a vaccine that will affect the virus. Last September, researchers reported the discovery of their biggest yet with a vaccine that appears to reduce infection rates around 30 percent in Thai volunteers, but the trial reap a lot of questions.
Moving Target
The researchers did not find the virus to mutate so that they can design a vaccine that will protect against viruses that are constantly changing.
Nabel team discovered two antibodies in the blood of HIV-infected patients who are not sick, although infected. These people are called non-progressors and researchers studying the immune system to find out why they control the virus better than most patients.
They later found the body's immune system cells called B-cells that make antibodies specifically, using new molecular tools that they find.
In another experiment, they managed to freeze one of the antibodies in the process of grafting and neutralize the virus, get a picture-level atoms in a process called x-ray crystallography.
Able to "see" what kind of structure allows the researchers designed the vaccine using a process called rational vaccine design, which is similar to a technique of making a drug called rational drug design, says Nabel.
The vaccine also allows for the design of gene therapy to help patients make antibodies themselves, or using the old technique with a transfusion of antibodies directly.
One of the antibodies, called VRC01, partially mimic the way the immune cells called CD4 T-cells embedded in a piece of the AIDS virus called gp120, the researchers said.
"Antibodies are attached to the virus that has not changed, and explain why they can neutralize such as various types of HIV that is incredible," said Dr. John Mascola, who worked on this study, in a statement.
"The discovery of this incredibly broad neutralizing antibodies to HIV and structural analysis that explains how they work is interesting developments accelerate our efforts to find a vaccine for HIV prevention to be used globally," NIAID Director Dr. Anthony Fauci said in a statement.
"In addition, the team used a technique to search for a new antibody is a new strategy that can be applied to design vaccines for other infectious diseases."
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