Early HIV-1 gene expression is also diminished in infected rat cell lines, but not in infected primary rat macrophages. (A) T-cell cultures were challenged with HIV-1NL4-3E- GFP pseudotyped with either JR-FL Env (n = 2) or VSV-G (human (n = 12); rat (n = 24)), or challenged with VSV-G pseudotyped HIV-2ROD-AE- GFP (human (n = 7); rat (n = 12)) and analyzed for GFP expression at day 3 after infection as described in Fig. 6. Results represent the arithmetic mean ± S.E.M. of the indicated number of independent T-cell cultures (p = 0.009; * = significant). (B) Kinetics of GFP expression in primary T-cell cultures from human donors or hCD4/hCCR5-transgenic rats infected with single-round YU-2 Env pseudotyped HIV-1NL4-3E- GFP. The percentage of GFP-positive cells was quantified every 2–3 days by flow cytometry. Results are the arithmetic mean ± S.D. from individual T-cell cultures. (C) Human T-cell lines SupT1, Jurkat, or PM-1, and rat T-cell lines Nb2 or C58, as well as (D) human adherent cell lines TZM, 293T, or HeLa, and rat adherent cell lines Rat2, RGE, XC, or HH16, and (E) primary macrophages from both species (human (n = 3); rat (n = 4)) were exposed to VSV-G pseudotyped HIV-1NL4-3E- GFP at a low MOI to achieve single cell infections. The MFI of GFP expression was determined on day 3 after infection (p = 0.2; n.s.). Results shown in (C-D) represent the arithmetic mean ± S.D. of triplicates. Circles in (E) indicate the arithmetic mean of triplicates from one experiment and the horizontal bar shows the arithmetic mean ± S.E.M. of all donors/animals analyzed.