Activation of dendritic cells in vitro. a-h) Expression of maturation markers CD40 (a,b), CD80 (c,d), CD86 (e,f), and MHC-II (g,h) on DC2.4 after 2 days of incubation with Motor-OMV or control samples (n = 3, mean + SD). i-l) Concentration of TNF-α (i), IL-6 (j), IL-12p40 (k), and IL-1β (l) secreted by DC2.4 incubated with Motor-OMV or control samples for 2 days (n = 3, mean + SD; UD = undetectable). **p < 0.01, ***p < 0.001, and ****p < 0.0001 (compared to Motor-OMV); ##p < 0.01 and ####p < 0.0001 (compared to OMV); one-way ANOVA.