Figure 3.

Human monoclonal antibody CB8-2 recognizes TSG101 on the surface of cells infected with different HIV strains and SIV. Histograms in panel A show TSG101 exposure on the surface of primary CD4 T-cells infected with HIV-1_NL4-3 (CXCR4), HIV-1_ME1 (CCR5), HIV-1 L10R/M46I/L63P/V82T/I84V (CXCR4, protease resistant) and CD4+ T-cells isolated from rhesus macaques PBMC infected with SIV_mac251. Infected (green) and uninfected (red) cells were incubated with antibody CB8-2 and a FITC-goat anti-human secondary antibody. The membrane integrity of cells positive for CB8-2 binding cells was assessed using 7AAD as shown in Panel B. The lower right quadrant shows cell surface expression of TSG101 on cells that exclude 7AAD. The upper right quadrant shows cells with compromised membrane integrity, as evidenced by the uptake of 7AAD. Panel C shows lack of binding of CB8-2 to MT-4 uninfected cells (Red) in the absence of permeabilization reagent, and positive binding when the cells were permeabilized (Green).