a–d, LPS binding by EVs preincubated with isotype control, anti-HMGB1 or anti-LBP antibodies (Ab) and incubated with FITC-LPS (500 μg) at 37 oC for 45 min as assessed by ImageStream flow cytometry (a,c) and the HEK-Blue TLR4 reporter cell assay (b,d). Combined data from three experiments are shown, and the horizontal lines represent mean. P values were determined by unpaired two-tailed t-test.