HIV's dynamic shield

The human immunodeficiency virus (HIV) can avoid antibody neutralization, whether the antibodies are generated in response to a vaccine or to the viral infection itself, but the mechanisms involved in the process have been unclear. In the December 12 Nature, Peter Kwong and colleagues at the National Institutes of Health, Maryland, USA, show that HIV-1 evades antibodies through conformational masking of receptor-binding sites (Nature, 420:678-682, December 12, 2002).

Kwong et al. explored the interactions of monomeric gp120 HIV envelope glycoprotein with 20 different antibodies, and observed that recognition by receptor-binding-site antibodies induced a conformational change in the bridging sheet and interdomain orientations. They suggest that these changes are implicated in a 'conformational masking' mechanism which enables HIV-1 to maintain receptor binding and simultaneously to resist neutralization.

In addition, they tested a soluble dodecameric receptor molecule and found that it neutralized primary HIV-1 isolates with great potency, showing that simultaneous binding ...