Cell-Cell Transmission Enables HIV-1 to Evade Inhibition by Potent CD4bs Directed Antibodies
Figure 5
Attachment of virus is blocked by preventing gp120-CD4 interaction.
(A) Schematic illustration of the experimental set up used to analyze virus attachment. (B) Attachment of virus is driven by binding to CD4. Attachment of HIV to CD4 negative (HeLa, A2.01) and related CD4 positive cells (TZM-bl, A3.01-CCR5) as well as stimulated, CD8 depleted PBMC was studied using GFP-labeled virus (JR-FLppiGFP). The gray-shaded areas represent the fluorescent signal obtained by flow cytometric analysis of the respective cell line in the absence of HIV. The black lines indicate fluorescence intensity of bound JR-FLppiGFP. (C) Influence of entry inhibitors on HIV attachment. Activity of 2F5 (100 µg/ml), 4E10 (100 µg/ml) and CD4-IgG2 (50 µg/ml) to block attachment of GFP-labeled virus (JR-FLppiGFP) to A3.01-CCR5 cells is shown. Histograms of one representative of three independently performed experiments are shown. (D) Inhibition of HIV attachment by CD4bs and gp41 directed agents. Attachment (MFI of GFP signal) achieved in absence of inhibitor was set to 100% and inhibitor activity expressed in relation to this value. Data depicted are means of three independent experiments, error bars denote SEM. Left panel: Attachment of Vpr-GFP labeled TN8 virus (NL4-3 envelope) to PBMC. Middle panel: Attachment of GFP-labeled virus (JR-FLppiGFP) to A3.01-CCR5. Right panel: Attachment of GFP-labeled virus (NL4-3ppiGFP) to A3.01-CCR5 cells (individual inhibitor concentration are listed in Table S2).