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. 2021 Nov 20;9(11):1365. doi: 10.3390/vaccines9111365

Figure 5.

Figure 5

SARS-CoV-2 spike-protein stimulation of human PBMCs and inhibition of spike-protein-induced IL-6 signaling. (A) PBMCs were incubated for 72 h with LPS (200 ng/mL, stimulation positive control) or recombinant SARS-CoV-2 S protein (1 µg/mL). The supernatant was collected, and IL-6 concentration was determined by ELISA. (B) Luciferase reporter cells were pre-incubated with various concentrations of pIL6RmAb or an IgG isotype antibody negative control (6.25 µg/mL). The supernatant from S protein-stimulated PBMCs was then added to the cells. After 24 h of incubation, Luciferase-detecting reagent was added and the bioluminescent signal was measured. The percentage of luciferase signal relative to no antibody treatment is shown. Student’s t-test and one-way ANOVA were used for statistical analysis. At least three independent experiments were performed, and error bars represent standard error of the mean. *** indicates p values < 0.001 of IL-6 secretion by the S protein treated PBMCs compared to that of no treatment negative control. * and ns (not significant) indicate p values < 0.05 and > 0.05, respectively, of pIL6RmAb-treated samples compared to that of no treatment negative control.