Fig 1: Activated ILC2 enhance dengue viral infection in monocytes.Ex vivo sorted and expanded ILC2 from healthy individuals were stimulated with IL-33 (50 ng/ml), IL-25 (50 ng/ml), IL-2 (100 IU/ml) for 48 h and a IL-13 and b GM-CSF ELISA assays were performed on the supernatants of ILC2 at 0, 12, 24, 48 hr time points (n = 4). To demonstrate the effect of ILC2 supernatant on monocytes, unstimulated ILC2 were incubated with IL-2 (100 IU/ml) and activated ILC2 were incubated with IL-33 (50 ng/ml), IL-25 (50 ng/ml), IL-2 (100 IU/ml) for 48 h and the supernatants were collected. Unstimulated and activated ILC2 supernatants were added to CD14 MACS separated monocytes and c MMR expression was measured after 48 h by flow cytometry. In the blocking conditions, anti-GM-CSF and anti-IL-4Ra were added for 1 h before adding supernatants of ILC2. Statistical significance was tested using one-way ANOVA with Tukey’s multiple comparison test, data representative of three independent experiments (n = 6). P * < 0.05. d Unstimulated and activated ILC2 supernatants were added on monocytes and cells were infected with DENV2 at an MOI of 2.5 and intracellular dengue E protein was stained after 48 h by flow cytometry. Statistical significance was tested using one-way ANOVA with Tukey’s multiple comparison test, data representative of three independent experiments (n = 5). P * < 0.05, *** <0.001. e Monocytes were treated with activated ILC2 supernatants for 48 h and infected with DENV2 (MOI 2.5). In the blocking conditions, monocytes were incubated with Mannan 20 µg/ml (Sigma, 9036-88-8) for 1 h prior to infection. Infection rate was measured after 48 h by flow cytometry. Statistical significance was tested using one-way ANOVA with Tukey’s multiple comparison test, data representative of three independent experiments (n = 5). P * < 0.05, ** <0.01. All error bars represent mean ± SD.