The human immunodeficiency virus (HIV) is infamous for being a wily opponent, evolving faster than the immune system can keep up with it. Even now, 25 years after the virus was discovered, efforts to create a vaccine against it have fallen flat. While scientists have engineered antibodies that provide broad protection against the virus, vaccines designed to trigger the production of these antibodies work in monkeys but fail to elicit any immunity whatsoever in humans. Now new research shows that vaccines might do better if they could stimulate the body to produce not one of these “super” antibodies but hundreds of milder ones that act, en masse, to take down HIV.
Researchers from Rockefeller University examined the blood of six “slow progressing” HIV patients–people who can be infected for a long time without getting sick because their bodies are able to sufficiently control the virus. Using a novel technique to identify HIV-antibody-producing cells in the blood, and then another new method to isolate the antibodies themselves, the researchers found 433 different antibodies from these patients that can bind to a particular protein–called gp140–that the virus needs in order to infect immune cells. Many of these human isolated antibodies were capable of neutralizing some strains of HIV in lab tests.
Previous efforts to engineer an HIV vaccine have targeted this protein, but failed to stimulate the human immune system to produce any of the four broadly neutralizing antibodies described to date. The newly discovered group of antibodies, however, provides insight into the body’s natural response to the virus. Unlike the man-made antibodies, none has a great individual impact. But together, they can successfully hold the virus in check. “Not a single one of them is like the ‘fantastic four,’ but the body doesn’t make the fantastic four,” says Michel Nussenzweig, a professor of molecular immunology at Rockefeller University, who led the research. “So maybe what this says is that the kind of vaccine you want is one that will make all these other little guys that, together, will be effective.” The research was published online in the journal Nature on Sunday.