Fig. 3

Binding of WT and AF-20 VLPs to Thle-3 and Hep3B cells vis FACS. The key of the figure indicates which VLP and cell type is being analyzed. a 1 × 10⁶ of either Thle-3 or Hep3B cells were incubated with increasing quantities of either WT or AF-20 AlexaFluor 488-labeled VLPs (4 × 10¹² to 4 × 10¹⁵, roughly 16 µg to 16 mg) for 1 h at 37 °C. Cells were then fixed and washed, and mean fluorescent intensity (MFI) was measure via FACSCalibur. Note that neither WT nor AF-20 VLPs bind particularly well to Thle-3 cells (negative for AF-20 antigen), whereas only AF-20 VLPs bind to Hep3B cells (positive for AF-20 antigen) until the number of particles overwhelms the system and creates non-specific binding effects. b For each cell type from a, the value obtained for WT VLPs was treated as “background” binding and was subtracted from the value obtained for AF-20 VLPs, which were considered “signal”. This aides in the visualization of increased specific binding of AF-20 VLPs to Hep3B cells before total particle number becomes too large and the signal plateaus