Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against Pseudomonas aeruginosa pneumonia

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Staphylococcus aureus-induced complement activation promotes tissue factor-mediated coagulation

There is extensive cross-talk between the complement system, the Toll-like receptors (TLR) and hemostasis. Consumptive coagulopathy is a hallmark of sepsis and often mediated through increased tissue factor (TF) expression.To study the relative roles of complement, TLRs and TF in Staphylococcus aureus (S. aureus)-induced coagulation.Lepirudin-anticoagulated human whole blood was incubated with the three S. aureus strains Cowan, Wood and Newman. C3 was inhibited with compstatin, C5 with eculizumab, C5a-receptor-1 and factor XIIa with peptide inhibitors, CD14, TLR2, and TF with neutralizing antibodies, and TLR4 with eritoran. Complement activation was measured by ELISA. Coagulation was measured by prothrombin fragment 1+2 (PTF1.2) using ELISA, and TF mRNA, monocyte surface expression and functional activity using qPCR, flow cytometry and ELISA, respectively.All three strains generated substantial and statistically significant amounts of C5a, TCC, PTF1.2, TF mRNA, TF surface expression on monocytes and TF functional activity. Inhibition of C5 cleavage most efficiently inhibited (P < 0.05) all six markers in strains Cowan and Wood and five markers in Newman. The effect of complement inhibition was shown to be completely dependent on C5aR1. The C5 blocking effect was equally potentiated when combined with blocking of CD14 or TLR2, but not TLR4. TF blocking significantly (P < 0.05) reduced PTF1.2 levels to baseline levels.S. aureus-induced coagulation in human whole blood was mainly due to C5a-induced mRNA upregulation, monocyte TF expression and plasma TF activity, thus underscoring complement as a key player in S. aureus-induced coagulation. This article is protected by copyright. All rights reserved

Elevated Terminal C5b-9 Complement Complex 10 Weeks Post Kidney Transplantation Was Associated With Reduced Long-Term Patient and Kidney Graft Survival

Background: The major reason for graft loss is chronic tissue damage, as interstitial fibrosis and tubular atrophy (IF/TA), where complement activation may serve as a mediator. The association of complement activation in a stable phase early after kidney transplantation with long-term outcomes is unexplored. Methods: We examined plasma terminal C5b-9 complement complex (TCC) 10 weeks posttransplant in 900 patients receiving a kidney between 2007 and 2012. Clinical outcomes were assessed after a median observation time of 9.3 years [interquartile range (IQR) 7.5–10.6]. Results: Elevated TCC plasma values (≥0.7 CAU/ml) were present in 138 patients (15.3%) and associated with a lower 10-year patient survival rate (65.7% vs. 75.5%, P < 0.003). Similarly, 10-year graft survival was lower with elevated TCC; 56.9% vs. 67.3% (P < 0.002). Graft survival was also lower when censored for death; 81.5% vs. 87.3% (P = 0.04). In multivariable Cox analyses, impaired patient survival was significantly associated with elevated TCC [hazard ratio (HR) 1.40 (1.02–1.91), P = 0.04] along with male sex, recipient and donor age, smoking, diabetes, and overall survival more than 1 year in renal replacement therapy prior to engraftment. Likewise, elevated TCC was independently associated with graft loss [HR 1.40 (1.06–1.85), P = 0.02] along with the same covariates. Finally, elevated TCC was in addition independently associated with death-censored graft loss [HR 1.69 (1.06–2.71), P = 0.03] as were also HLA-DR mismatches and higher immunological risk. Conclusions: Early complement activation, assessed by plasma TCC, was associated with impaired long-term patient and graft survival

Elevated Terminal C5b-9 Complement Complex 10 Weeks Post Kidney Transplantation Was Associated With Reduced Long-Term Patient and Kidney Graft Survival

Background: The major reason for graft loss is chronic tissue damage, as interstitial fibrosis and tubular atrophy (IF/TA), where complement activation may serve as a mediator. The association of complement activation in a stable phase early after kidney transplantation with long-term outcomes is unexplored. Methods: We examined plasma terminal C5b-9 complement complex (TCC) 10 weeks posttransplant in 900 patients receiving a kidney between 2007 and 2012. Clinical outcomes were assessed after a median observation time of 9.3 years [interquartile range (IQR) 7.5–10.6]. Results: Elevated TCC plasma values (≥0.7 CAU/ml) were present in 138 patients (15.3%) and associated with a lower 10-year patient survival rate (65.7% vs. 75.5%, P Conclusions: Early complement activation, assessed by plasma TCC, was associated with impaired long-term patient and graft survival

Complement component 5 does not interfere with physiological hemostasis but is essential for Escherichia coli-induced coagulation accompanied by Toll-like receptor 4

There is a close cross-talk between complement, Toll-like receptors (TLRs) and coagulation. The role of the central complement component 5 (C5) in physiological and pathophysiological hemostasis has not, however, been fully elucidated. This study examined the effects of C5 in normal hemostasis and in Escherichia coli-induced coagulation and tissue factor (TF) up-regulation. Fresh whole blood obtained from six healthy donors and one C5-deficient individual (C5D) was anti-coagulated with the thrombin inhibitor lepirudin. Blood was incubated with or without E. coli in the presence of the C5 inhibitor eculizumab, a blocking anti-CD14 monoclonal antibody (anti-CD14) or the TLR-4 inhibitor eritoran. C5D blood was reconstituted with purified human C5. TF mRNA was measured by quantitative polymerase chain reaction (qPCR) and monocyte TF and CD11b surface expression by flow cytometry. Prothrombin fragment 1+2 (PTF1·2) in plasma and microparticles exposing TF (TF-MP) was measured by enzyme-linked immunosorbent assay (ELISA). Coagulation kinetics were analyzed by rotational thromboelastometry and platelet function by PFA-200. Normal blood with eculizumab as well as C5D blood with or without reconstitution with C5 displayed completely normal biochemical hemostatic patterns. In contrast, E. coli-induced TF mRNA and TF-MP were significantly reduced by C5 inhibition. C5 inhibition combined with anti-CD14 or eritoran completely inhibited the E. coli-induced monocyte TF, TF-MP and plasma PTF1·2. Addition of C5a alone did not induce TF expression on monocytes. In conclusion, C5 showed no impact on physiological hemostasis, but substantially contributed to E. coli-induced procoagulant events, which were abolished by the combined inhibition of C5 and CD14 or TLR-4