Combined Inhibition of Complement and CD14 Attenuates Bacteria-Induced Inflammation in Human Whole Blood More Efficiently Than Antagonizing the Toll-like Receptor 4–MD2 Complex

Abstract

Background. Single inhibition of the Toll-like receptor 4 (TLR4)–MD2 complex failed in treatment of sepsis. CD14 is a coreceptor for several TLRs, including TLR4 and TLR2. The aim of this study was to investigate the effect of single TLR4-MD2 inhibition by using eritoran, compared with the effect of CD14 inhibition alone and combined with the C3 complement inhibitor compstatin (Cp40), on the bacteria-induced inflammatory response in human whole blood.Methods. Cytokines were measured by multiplex technology, and leukocyte activation markers CD11b and CD35 were measured by flow cytometry.Results. Lipopolysaccharide (LPS)–induced inflammatory markers were efficiently abolished by both anti-CD14 and eritoran. Anti-CD14 was significantly more effective than eritoran in inhibiting LPS-binding to HEK-293E cells transfected with CD14 and Escherichia coli–induced upregulation of monocyte activation markers (P < .01). Combining Cp40 with anti-CD14 was significantly more effective than combining Cp40 with eritoran in reducing E. coli–induced interleukin 6 (P < .05) and monocyte activation markers induced by both E. coli (P < .001) and Staphylococcus aureus (P < .01). Combining CP40 with anti-CD14 was more efficient than eritoran alone for 18 of 20 bacteria-induced inflammatory responses (mean P < .0001).Conclusions. Whole bacteria–induced inflammation was inhibited more efficiently by anti-CD14 than by eritoran, particularly when combined with complement inhibition. Combined CD14 and complement inhibition may prove a promising treatment strategy for bacterial sepsis.

Dual inhibition of complement and Toll-like receptors as a novel approach to treat inflammatory diseases—C3 or C5 emerge together with CD14 as promising targets

“…shown to interact with CD14 [63]. Recently, eritoran was compared with a neutralizing anti-CD14 antibody in a human whole-blood model with respect to effect on Gram-negative and -positive, bacteria-induced inflammation [64]. In line with previous findings, eritoran and anti-CD14 mostly inhibited Gramnegative-induced inflammation, whereas Gram-positive inflammation was more complement dependent, possibly explaining the lack of effects of eritoran in a broad sepsis population.…”

The outer membrane protein Tp92 of Treponema pallidum induces human mononuclear cell death and IL‐8 secretion

“…CD14 not only transfers the identified lipoprotein signal to TLR2 but also transfers the identified LPS signal to TLR4. 55 Our data showed that silencing of TLR2 inhibits cell death, but silencing of TLR4 fails to inhibit cell death, suggesting that the Tp92 protein induces THP-1 cell death via CD14 and/or TLR2. A study showed that TLR2 activates the inflammasome NLRP3, 56 but there has been no report on whether TLR2 activates NLRC4 and mediates atypical pyroptosis.…”

“…In addition, anti‐CD14 Ab treatment completely inhibits cell death, and anti‐TLR2 Ab treatment partially inhibits cell death. CD14 not only transfers the identified lipoprotein signal to TLR2 but also transfers the identified LPS signal to TLR4 . Our data showed that silencing of TLR2 inhibits cell death, but silencing of TLR4 fails to inhibit cell death, suggesting that the Tp92 protein induces THP‐1 cell death via CD14 and/or TLR2.…”

Involvement of complement activation in the pulmonary vasoactivity of polystyrene nanoparticles in pigs: unique surface properties underlying alternative pathway activation and instant opsonization

“…8,10 The importance of revisiting this issue lies in the clinical relevance of C being or not being involved in infusion reactions, since C-based predictive assays and C-inhibitionbased preventive measures are still open, largely unexplored options in combating these adverse immune reactions. 27 Inhibition of C activation as adjunct therapy against acute life-threatening immunoactivation is getting increasing recognition, [28][29][30] so premature or unfounded exclusion of C activation as a key contributing mechanism of infusion reactions may be misleading in this field. The original observations giving rise to questioning the role of C in the significant pulmonary hypertensive effect of 500 nm spherical PS-NPs in pigs was the lack of C activation in hirudinized pig whole blood in vitro.…”