Anti-MD-2 18H10 mAb binding to TLR4-HEK293 cells. (A) FACS analysis of APC-conjugated anti-MD-2 18H10 mAb binding to TLR4-HEK293 cells in the presence of 10% normal plasma (n = 4), 10% septic plasma (n = 4), or recombinant soluble MD-2 (sMD-2). Mean fluorescence index indicates MFI; a.u., arbitrary units. (B) Loss of anti-MD-2 18H10 mAb binding to TLR4-HEK293 cells in the presence of septic plasma that has previously been affinity-depleted on TLR4-HEK293 cells, compared with septic plasma that has been mock-depleted on nontransfected HEK293 cells. This is 1 representative experiment from 3 similar experiments. (C) LPS activation of TLR4-HEK293 cells in the presence of 2% septic plasma that has been previously affinity-depleted on TLR4-HEK293 cells, compared with septic plasma that has been mock-depleted on nontransfected HEK293 cells. Mean ± 1 SD of triplicates. This is 1 representative experiment from 3 similar experiments.