HIV's sugar shield

Most individuals infected with HIV-1 develop neutralizing antibodies (Nab) capable of eliminating autologous viruses in vitro, but the role of these antibodies in vivo has been unclear. In the March 20 Nature, Xiping Wei and colleagues at the University of Alabama at Birmingham, US, show that HIV manages to escape the Nab response through mutations in the env gene and selected changes in glycan packing (Nature, 422:307-312, March 20, 2003).

Wei et al. examined plasma from patients with acute HIV infection and detected autologous Nab 52 days after detection of HIV-specific antibodies. They observed that the viral inhibitory activity of Nab resulted in complete replacement of neutralization-sensitive virus by successive populations of resistant virus with mutations in the env gene. These mutations were unexpectedly sparse, did not map generally to known neutralization epitopes, and primarily involved changes in N-linked glycosylation. In addition, they showed that Nab-selected...