TAT and HIV-1 infection: Sera from days 28, 56, 70 and 90 from animals immunized with the rNDVs expressing gp140, gp120 and gp160 were evaluated in the TZM bl assay (which assays HIV-1 infection by measuring Tat-regulated luciferase expression in an indicator cell line) for the ability to neutralize homologous clade B tier 1 HIV-1 strains BaL.26 and MN.3 and heterologous clade B tier 2 HIV-1 strains RHPA4259.7 and TRO.11.