ERVW-1 and viral infectious disease: Interestingly, the ability to bind different CD4i Env conformations appears to correlate with the potency and breadth of cluster A antibodies in their ability to evoke ADCC in two distinct systems: one designed to assay killing upon initial viral binding (gp120-coated RFADCC assay [29]) and the other during active viral infection (luciferase assay with cells infected with Nef-deficient IMCs [24, 27]).