hTIM1 promotes infection mediated by a range of viral entry proteins.

<p>(A) Human 293T cells do not express TIM1. 293T and control cells were stained with anti-hTIM1 antibody (red) or with mFc (black). (B) Murine 3T3 cells do not express TIM1. 3T3 and control cells were stained with anti-mTIM1-PE antibody (red). Unstained cells (black) and cells stained with anti-mIFNγ-PE (blue) served as negative controls. (C) Exogenous hTIM1 increases the entry of various pseudoviruses in 293T cells. 293T cells were transfected with plasmids expressing hTIM1 or, as a negative control, hACE2. 48 h later cells were infected with MLV pseudoviruses or WNV VLPs, both carrying the GFP reporter gene. The following day, GFP expression was quantified by flow cytometry. Fold changes in entry were calculated by dividing mean fluorescence intensity observed in hTIM1-expressing 293T cells by those in hACE2-expressing 293T cells. Figure shows mean+SD from three independent, duplicated experiments. (D) hTIM1 usage by pseudoviruses was similarly assessed in 3T3 cells transduced with hTIM1 or hACE2. (E) Entry inhibition by an anti-hTIM1 antibody parallels hTIM1 use by pseudoviruses. 293T cells transduced with hACE2 (mock) or hTIM1 were preincubated for 30 min at room temperature with medium alone (none), the anti-hTIM1 antibody 3D1 or mIgG, and infected with pseudoviruses overnight in the presence of the respective blocking agents. Infection levels were normalized to those of untreated hTIM1-expressing cells. Figure shows mean+SD from two independent, duplicated experiments. (F) Human Huh7 cells express high levels of TIM1. Huh7 cells and control cells were stained for TIM1 expression as in A. (G) An anti-hTIM1 antibody inhibits entry of various pseudoviruses in Huh7 cells. Huh7 cells were incubated with antibodies and infected as in E. Infection levels were assessed 48 h later as in C and normalized to those of untreated cells. Figure shows mean+SD from three independent, duplicated experiments.