HIV gp120 binding affects differential expression of T-cell but not DC genes. (A) Binding of HIV-1 envelope proteins to MDDCs. Day-6 immature MDDCs (5 × 10⁶) were incubated with biotinylated monomeric gp120 (BaL strain) and trimeric gp140 (AD8 and UG037 strains) ranging from 0 to 0.15 μg/μL. Biotinylated gp120/140 binding was determined by flow cytometry using PE-conjugated streptavidin. The geometric means of the fluorescent intensity data for the UG037 strain of trimer are displayed in the histogram. (B) Biologic activity of gp120 species. Naive CD4 T cells (5 × 10⁶) were incubated with monomeric gp120 (BaL strain) and trimeric gp140 (AD8 and UG037 strains) at 50 ng per 10⁶ cells for 24 hours. Differential expression of the GUCY2D and CCL3 genes was determined by QPCR. The fold change in gene expression compared with mock-treated cells is displayed in the histogram. (C) Differential MDDC gene expression in response to monomeric and trimeric HIV-1 envelope species. Day-6 immature MDDCs were treated with either recombinant monomeric gp120 (BaL strain) or 1 of 2 trimeric gp140 stocks (AD8 and UG037 strains) for 6, 24, and 48 hours (monomer) or 2, 6, and 24 hours (trimers). Global DC gene expression was determined using Illumina gene expression chips (trimeric gp140s). A representative MA plot is shown with 1.5-fold change lines for trimeric gp140 (UG037 strain) 24 hours after treatment.