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Scientists find antibody road map to AIDS vaccine

PARIS (AFP) ― Scientists on a quest for an antibody-based AIDS vaccine said Wednesday they found promising clues in the uncommonly “robust” natural immune response of a patient in Africa.

Studying blood samples over a three-year period after the person was infected, researchers were witness to a microscopic battle between the virus and antibodies ― both evolving as they sought to gain the upper hand.

For the first time, scientists were able to follow the full chain of events leading to the patient naturally producing broadly neutralizing antibodies (BnAbs) ― so called because they attack different strains of the human immunodeficiency virus (HIV) that causes AIDS.

“The current research... fills gaps in knowledge that have impeded development of an effective vaccine for a virus that has killed more than 30 million people worldwide,” said a statement from Duke Medicine, which participated in the study by a team of researchers in the United States and Malawi.

“We learned from this individual how the antibodies get induced with the hope that this information can be a map for how to induce these antibodies as a preventive vaccine,” added team leader Barton Haynes, director of Duke University’s Human Vaccine Institute.

Antibodies are the foot soldiers of the immune system, latching onto viruses or microbial intruders and tagging them for destruction by specialized “killer” cells.

Most antiviral vaccines are made by priming antibodies to recognize germs, but the method has not yet been successful in AIDS control.

One of vaccine developers’ fiercest foes, the HIV virus typically evolves too fast to ever be left open to antibody attack.

The individual in the study, from an African country that is not specified, is one of about 20 percent of HIV-infected people whose immune systems naturally produce BnAbs.

Unfortunately, this generally only happens two to four years after infection and is of no help to the host who will still develop AIDS if not treated with anti-retroviral drugs.

“When broad neutralizing antibodies are made they are no help to the person already infected. The notion is however; if they are present before infection, then they can prevent infection and prevent insertion of the virus genetic material into the host genetic material,” Haynes told AFP of the research published in the journal Nature.

In monkeys, BnAbs have shown to prevent infection.

A BnAbs-based vaccine is being keenly pursued in the battle against AIDS, an immune system-wrecking disease first recognized in 1981.