HEALTH. Llamas hold the key to breakthrough in AIDS research

Thirty years after AIDS (acquired immune deficiency syndrome) was discovered, scientists continue to struggle with the disease caused by the HIV (human immunodeficiency virus), with current medical solutions only providing symptomatic relief.

However, hope is around the corner. The gentle and endearing South American llamas may hold the clues to a vaccine against HIV, one of the deadliest killers today.

Molecular biologist Robin A Weiss told BusinessLine , “Llamas and camels are unique in the antibodies they produce — a discovery made in 1993. The usual antibodies that humans or other mammals produce, have what are called heavy chains, and light chains.”

For some reason, llamas and camels make the usual antibodies. But they also make ones that only have heavy chains. And that means those antibodies recognise an antigen, such as the envelope of HIV, in a manner similar to that of other antibodies. Plus, it’s on a very small bit of the protein.” Weiss, 75, a pioneer in AIDS research and Professor at the University College of London, who is visiting India, has been part of the expert team looking into llama antibodies. He said that the small size of these antibodies allows them to fit into the crevices of different strains of the HIV virus and neutralise them, something naturally produced human antibodies are unable to do. These animal antibodies can be used as a model to develop a successful vaccine.

However, that’s not all. These curious antibodies are also being studied for their potential to block HIV from entering the body through genitalia.

“These antibodies are tough little molecules. You can heat them up, cool them down, change their environment from alkaline to acidic and they still work. For example, if they can be injected as a gel into the subject, they could zap the virus (HIV) and neutralise it. And it really doesn’t matter if the internal environment undergoes a change, as it does during sex. They would still be protected,” Weiss said. “This is about to undergo an experimental trial in macaques (species of monkeys),” he added.

Weiss said introducing llama antibodies into the human body is possible and would, theoretically, be harmless. Further, hybrid antibodies with a part, derived from llama, that recognises HIV, and the rest from humans has also been made. The research, started nine years ago, has given hope to Weiss, who has been working in the field of AIDS research for over 30 years, in search of a vaccine. “We will get there. But it’s going to be a long haul,” Weiss said.

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