FIGURE 1

Soluble factors secreted by human CD4⁺ T cells inhibit VSV infection. A, THP-1 cells were infected for 16 hours with VSV-GFP. GFP expression was analyzed by flow cytometry. Representative FACS plots showing THP-1 cells left uninfected or infected with VSV-GFP in the presence or absence of 100 U/ml rhIFN-αA and/or a neutralizing anti-hIFNAR2 antibody. B, THP-1 cells were left uninfected (square) or were infected for 16 hours with VSV-GFP in the absence (triangle) or presence (circles) of increasing concentrations of rhIFN-αA. GFP expression was analyzed by flow cytometry. C, THP-1 cells were left uninfected (■) or were infected for 16 hours with VSV-GFP. Cells were treated at the time of infection with either media alone (▲) or with increasing doses of conditioned media from T cells polarized with the following conditions: Neutralized (anti-IFN-γ, anti-IL-4, anti-IL-12, and anti-IFNAR2), □; IL-12, (rhIL-12, anti-IFN-γ, anti-IL-4, and anti-IFNAR2) ;▵ IFN-αA, rhIFN-αA, anti-IFN-γ, anti-IL-4, and anti-IL-12) ∇; or IL-12 + IFN-αA, (rhIL-12 and rhIFN-αA in the presence of anti-IFN-γ and anti-IL-4) ○. GFP expression was analyzed by flow cytometry. *, p < 0.05 versus neutralized. D, THP-1 cells were infected for 16 hours with VSV-GFP in the absence or presence of T cell conditioned media from T cells which were left unstimulated (black bars) or were restimulated on day 7 for 24 hours with plate-bound anti-CD3 (hatched bars). GFP expression was analyzed by flow cytometry. E, THP-1 cells were cultured for 24 hours in the absence or presence of 100 U/ml rhIFN-αA or T cell conditioned media derived from cells polarized as indicated in the figure. Cells were then washed and then infected for an additional 24 hours with VSV-GFP, and viral replication was quantified by plaque assay.