FIG. 4.

Susceptibility of various cell lines to transduction by HTLV-1 pseudotyped virus parallels their ability to bind HTSU-IgG. (A) Titer of MLV(HTLV-1) and MLV(A-MLV) for various cell lines. Target cells were transduced with 10-fold dilutions of cell-free pseudotyped virus containing an EGFP indicator provirus. The relative titer was determined from the percentage of cells positive for the expression of EGFP as measured by flow cytometric analysis. These titers represent the means for three to seven independent experiments; each error bar represents the SEM. Pairwise comparison was performed using the Tukey test. Grey, titer of MLV(A-MLV); black, titer of MLV(HTLV). (B) Relative binding of HTSU-IgG to various cell lines. Binding of HTSU-IgG (200 ηg/ml) was determined by flow cytometric analysis, as described above. The amount of specific binding was determined by subtracting the MFI of SUA-IgG binding (500 ηg/ml) from the MFI of HTSU-IgG binding. For each experiment, the values were normalized to the amount of binding of HTSU-IgG to 293 cells within that experiment. The numbers represent the means for three independent experiments; error bars represent SEM). Pairwise comparison was performed using the Tukey test; significance was determined at the 0.05 level.