The rare super-antibodies that destroy HIV

A recent study sheds new light on a rare immune response to the virus—and could bring researchers a step closer to developing a vaccine. When a person becomes infected with HIV, the immune system kicks into gear: Immune cells called B cells build antibodies, tiny protein warheads that seek out and destroy viruses. But because HIV mutates so rapidly, these antibodies are generally ineffective—by the time B cells learn to build antibodies against one version of HIV, a new viral mutant has already taken over. In some patients, the immune system manages to make antibodies that actually work against a broad spectrum of HIV mutants, but those antibodies typically emerge only five or six years into the infection. And by that point, their efforts may be too little, too late. “Once you already have an established infection with millions or billions of viral particles in an infected individual, even with a potent...