Scientists Discover Key HIV Defense

Researchers at the National Institutes of Health and Boston's Dana Farber Cancer Institute have reported that they discovered a key tactic HIV uses to evade antibody attacks on the virus. The core of HIV's gp120 protein, an area of the virus exposed when HIV latches onto and infects immune system cells, was shown to be composed of very flexible parts that allow it to take on different shapes, effectively disguising it from attacking antibodies. Antibodies that do latch onto the protein are less able to kill the virus because the changing shapes make it difficult for the antibodies to firmly bind to it. 'It's a blurry, moving structure that is very difficult for the immune system to deal with,' says researcher Joseph Sodroski. The researchers say their discovery helps explain why it has been so difficult for scientists to develop an HIV vaccine that induces an effective antibody response to the virus.