CCR5 Mimicry by Sulfated Human Anti-HIV-1 Antibodies

HIV-1 envelope glycoprotein interaction with a principal coreceptor, CCR5, requires sulfated tyrosines on the CCR5 amino terminus. In this issue of Cell, Choe et al. identified tyrosine-sulfated, neutralizing antibodies against HIV-1 that apparently mimic CCR5. The results demonstrate for the first time that a natural posttranslational modification of an antibody can contribute substantially to antigen recognition.