Since its discovery and rapid spread in the 1980s, scientists and physicians have desperately tried to understand the HIV virus and develop effective treatments. Unfortunately, HIV is a tricky virus that evades typical immune responses.

During a successful immune system response to a foreign body, white blood cells produce antibodies that target the invader. These antibodies then flag the foreign body for destruction by other immune cells. For the most part, HIV evades these immune defenses, but rare individuals develop antibodies that effectively block multiple strains of the virus. Researchers are now showing that these antibodies can also act as treatments in other HIV patients.

HIV has several ways of avoiding the immune response. Unlike most viruses, HIV specifically attacks a type of white blood cell that is critical to our immune system. During replication, the HIV virus also picks up many new mutations, which often change it enough that any antibodies produced earlier during the infection no longer recognize it. There are very few parts of the virus where changes due to mutations would cause it to be unable to enter cells; even fewer antibodies have been identified that bind to these locations.