High-throughput assay to identify inhibitors of Vpu-mediated down-regulation of cell surface BST-2.

Bone marrow stromal cell antigen 2 (BST-2, also known as Tetherin) inhibits HIV-1 release and thereby severely impairs viral replication. HIV-1 accessory protein Vpu induces the down-regulation of cell surface BST-2, and counteracts the antiviral function of BST-2. Blocking Vpu-mediated down-regulation of cell surface BST-2 is viewed as a new opportunity for developing anti-HIV drugs. In this study, we have developed a high-throughput cell-based ELISA to identify small molecules that antagonize HIV-1 Vpu function and consequently inhibit HIV-1 replication through rescuing the antiviral activity of host BST-2. This cell-ELISA shows an excellent correlation with results obtained by flow cytometry (FACS). Under optimal conditions, a Z' factor of 0.605 was achieved in a 96-well format. Together, these results demonstrate that this assay can be used to quantify the cell surface level of BST-2 and be adapted to a high-throughput screening for novel anti-HIV compounds.