Progress in targeting HIV-1 entry.

Current HIV entry inhibitors target the binding of the viral envelope glycoprotein gp120 to cellular CD4 and co-receptors, or block a late stage of the fusogenic activation of adjacent gp41. New targets are suggested by the role of cell surface protein disulfide isomerase (PDI), which attaches to the primary receptor CD4 close to the gp120-binding site. This could enable PDI to reduce gp120 disulfide bonds, which triggers the major conformational changes in gp120 and gp41 required for virus entry. Inhibiting cell surface PDI prevents HIV-1 entry. The new potential targets outlined are PDI activity as well as the sites of PDI-CD4 and PDI-gp120 interaction.