The LPS used was from E. coli O111:B4 (Sigma, L2630) and also E. coli O26:B6 (Sigma L2762). A final LPS exposure concentration of 0.2 ng l−1 (well below its critical micelle concentration ) was used in all experiments bar as noted for some of the ITC measurements. A final LBP exposure concentration of 2 ng l−1 LBP and a mixture with final exposure concentration of LPS (0.2 ng l−1) and LBP (2 ng l−1), incubated for 10 min with PPP, were also used (only confocal studies).