Fig. 2. Saturable resistance to primate lentiviruses and N-MLV in CV-1 cells. (A) HIV-2 is restricted in CV-1 (AGM) but not in human (TE671) cells. CV-1 cells (filled symbols) or TE671 cells (open symbols) were inoculated with a fixed dose of HIV-2-GFP vector in the presence of increasing amounts of abrogating HIV-2-Puro particles. The percentage of HIV-2-GFP-infected cells as a function of abrogating virus dose is plotted. Abrogating virus dose is given in infectious units (i.u.) measured as puromycin-resistant colony formation on TE671 cells. (B) Abrogation of SIV-GFP restriction by HIV-2-Puro particles. CV-1 cells were inoculated with a fixed dose of SIV-GFP in the presence of abrogating HIV-2 particles, as in (A), and the percentage of SIV-GFP infected cells is plotted. (C) Resistance of CV-1 cell to N-GFP is saturable. CV-1 cells were inoculated with a fixed dose of N-GFP in the presence of increasing levels of abrogating N-Neo or B-Neo vector particles. Abrogating virus dose is given as MDTF i.u. as measured by G418-resistant colony formation.