Figure 1.

Ectopic expression of TIM-1 enhances CHIKV infection (A) Surface expression of Axl and TIM-1 wild type (WT) proteins on parental HEK293T and stably transduced cells was evaluated by monoclonal antibody staining and flow cytometry. Cells stained with an isotype IgG were used as control. (B) Parental, Axl WT and TIM-1 WT expressing cells were challenged with ECSA 3′GFP-CHIKV at indicated MOI and (C) for different infection durations at MOI of 0.01. Infection levels were assessed by flow cytometry and plotted as percentage of GFP positive cells. (D) Parental and TIM-1 WT expressing cells were challenged with CHIKV strains of ECSA 3′GFP-CHIKV (MOI = 0.01), WA 5′GFP-CHIKV (MOI = 0.01) and Asian mc-CHIKV (MOI = 0.1) genotypes and infection assessed by flow cytometry. (E) HEK293T cells expressing TIM-1 were pre-incubated for 30 min with increasing concentrations of TIM-1 polyclonal antibody (black bars) or isotype control antibody (mock, white bars) before inoculation with ECSA 3′GFP-CHIKV at MOI of 0.01. After 4 h the cells were washed and infection levels analyzed by flow cytometry 20 h later as in (B) and (C). Error bars represent standard error of the mean (SEM) of three biological replicates. Statistical significance was calculated using a Dunnet’s multiple comparisons test (2way ANOVA) ns > 0.05, * p < 0.05, ** p < 0.01, *** p < 0.001 and **** p < 0.0001.