A CD4-mimetic compound enhances vaccine efficacy against stringent immunodeficiency virus challenge.

The envelope glycoprotein (Env) trimer ((gp120/gp41)) mediates human immunodeficiency virus (HIV-1) entry into cells. The "closed," antibody-resistant Env trimer is driven to more open conformations by binding the host receptor, CD4. Broadly neutralizing antibodies that recognize conserved elements of the closed Env are potentially protective, but are elicited inefficiently.