Figure 1

Enhanced HIV entry into macrophages is associated with sensitivity to neutralizing mAb b12 and a broadly neutralizing HIV-infected patient serum. HIV luciferase reporter viruses pseudotyped with primary HIV Envs cloned directly from brain, spleen, or lymph node tissues from AIDS patients with HAD were incubated with a range of concentrations of human mAb b12 (A and D), soluble CD4 (sCD4; B and E), or HIV-1 neutralizing patient serum (PS; C and F) 1 h prior to infection of Cf2 cells transiently expressing CD4 and CCR5. Cells were harvested 48 h post infection and assayed for luciferase activity. (A, B, C) The concentrations at which luciferase expression was reduced by 50% compared to infection in the absence of mAb (IC₅₀) were calculated and plotted as a function of MDM entry [10, 14]. R and p values were determined by Spearman correlation. (D, E, F) b12, sCD4, and PS IC50s of HIV Envs with low to intermediate MDM infectivity (< median; median = 16,658 relative luciferase units) were compared to Envs with intermediate to high MDM infectivity (> median). Monocyte-derived macrophages (MDM) were isolated from peripheral blood mononuclear cells from healthy HIV-1-negative donors by plastic adherence and cultured in RPMI 1640 medium supplemented with 10% FBS, and 10 ng/ml macrophage colony stimulating factor (M-CSF) [8]. The MDM entry and sequence data were reported previously [10, 14]. Env clones containing either the N386 or D386 variant are indicated by closed and open symbols, respectively. MDM were prepared as above in 48-well plates and infected with 2 × 10^{4 3}H cpm RT units of Env pseudotyped virus stock. Cells were lysed 6 days post-infection and assayed for luciferase activity. Significant differences between groups (p < 0.05, Mann-Whitney test) are indicated by a *.