HIV-1 Pseudovirus Neutralization Assay

Virus neutralization was measured using HIV-1 pseudoviruses with TZM-bl target cells as described previously (20 (link)). HIV-1 pseudoviruses were produced in transfected 293T cells using a ProFection kit (Promega) or polyethylenimine (PEI) MAX40,000 (Polysciences). Prior to testing in the neutralization assay, sera were heat-inactivated (56°C for 30 min). Virus was incubated for 1 h at 37°C with serially diluted sera and then added to TZM-bl cells in the presence of diethylaminoethyl-dextran (Sigma). Virus infection was determined after 48 h using the Bright-Glo Luciferase Assay System (Promega). For peptide absorption assay, V3 peptide (40 μg/mL) was added to serum 1 h before the addition of virus.