Figure 2.

Susceptibility of hMDM to different human coronaviruses. Human MDM were inoculated with different coronaviruses (hCoV-229E, MERS-CoV, SARS-CoV-1 and SARS-CoV-2) using an MOI of 1 TCID₅₀/cell. Mock-infected cells were included as controls. After incubating the cells for 1.5 hours, the inoculum was removed, the cells washed, and fresh medium added. At 24 hpi, dsRNA in the cells was detected with a specific antibody and nuclei were stained with DAPI; the scale bar represents 40 µm. (A) The percentage of dsRNA-positive hMDM was calculated for 10 fields per condition (B). In (C) virus titers are shown. The same experiment was repeated with hCoV-229E, SARS-CoV-1 and SARS-CoV-2, and infected cells were quantified at 24, 48 and 72 hpi (D). The relative number of total hMDM per well was calculated taking as reference the number of cells at 24 hpi (E). The data from three independent experiments run in triplicates are shown in each panel. Statistically significant differences between the conditions are indicated by different superscript letters in (B, C) (p < 0.05), and by asterisks in (D, E) (****p ≤ 0.0001).