Human Alveolar Macrophages Synthesize Active Complement Components C6, C7, and C8 in Vitro

Pettersen, H. B.; Johnson, Egil; Hetland, Geir

doi:10.1111/j.1365-3083.1987.tb01082.x

Cited by 22 publications

(22 citation statements)

References 7 publications

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“…Each sample was separated into plasma and hemocytes. The complement activation system in the plasma sample was modified in various ways by the following treatments [5, 11]: (1) adding EDTA to a final concentration of 10 m M (to inactivate both the classical and alternative pathways); (2) adding EGTA to a final concentration of 10 m M and Mg 2+ to a final concentration of 3.5 m M (to inactivate the classical pathway): (3) heat inactivation at 50°C for 20 min (to inactivate the alternative pathway), and (4) adding only phosphate-buffered saline (PBS; 200 µl) as control (no modification of the complement pathways). Hemocytes were washed twice with PBS and then resuspended in these plasma samples.…”

Section: Methodsmentioning

confidence: 99%

Reduction of Neutrophil Activation by Vitamin E Modified Dialyzer Membranes

Omata¹,

Higuchi²,

Demura

et al. 2000

Nephron

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Background/Aim: Transient leukopenia during hemodialysis due to neutrophil activation is attributed to bioincompatibility of the dailysis membrane, but the mechanism remains unclear. We studied the mechanism of neutrophilic activation by comparing a vitamin E modified membrane (CLEE) and a regular cellulose membrane (CLSS). Methods: (1) CLSS and CLEE membranes were used in a crossover clinical study in 7 chronic hemodialysis patients. Neutropenia, CD11b expression, and plasma C3a and myeloperoxidase concentrations were compared between the two dialyzer membranes. (2) Normal blood was circulated through CLEE and CLSS minimodels, and the same parameters were compared. (3) Blood samples with modified complement activities (EDTA: both classical and alternative pathways inactivated; EGTA+Mg: classical pathway inactivated; heating: alternative pathway inactivated; control: no modification) were incubated in the CLSS minimodel, and the neutrophilic activation was compared. Results: In clinical hemodialysis, neutropenia, CD11b expression, and C3a and myeloperoxidase levels were significantly lower when CLEE membranes were used. The same tendency was observed in minimodels. However, the degrees of inhibition in clinical dialysis, especially at the venous line, were significantly higher than in minimodels. As compared with controls, CD11b expression and myeloperoxidase level were significantly lower when both classical and alternative pathways were inactivated or when the classical pathway alone was inactivated, but were not significantly different when the alternative pathway alone was inactivated. Conclusions: Vitamin E modification of the dialyzer reduces some reactions of neutrophilic activation, such as CD11b expression and myeloperoxidase release, more effectively in the clinical situation than in ex vivo models, suggesting a possible effect of vitamin E in inhibiting bioreactions due to pyrogen in the dialysate. The classical complement pathway is required in membrane-induced neutrophilic activation, at least during the initial stage.

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Section: Methodsmentioning

confidence: 99%

Reduction of Neutrophil Activation by Vitamin E Modified Dialyzer Membranes

Omata¹,

Higuchi²,

Demura

et al. 2000

Nephron

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“…Therefore, allotype conversion experiments, similar to those used in identifying the liver as the primary source of the complement proteins C3, C6, C8 and factor B, were not possible [5-71. Following the identification of the C7 M/N polymorphic system, similar experiments were performed on a group of liver transplant recipients which suggested that the liver contributed only 10 YO of the circulating C7 at time points later than 6 weeks post-transplantation [8]. In contrast, monocytes, macrophages, fibroblasts and astroglioma cell lines have directly or indirectly been shown to be capable of producing C7 [9-121.…”

Section: Introductionmentioning

confidence: 99%

Organ‐specific contribution to circulating C7 levels by the bone marrow and liver in humans

et al. 1996

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Many cells types can produce complement component C7, although the major site of C7 synthesis is unknown. Conversion from recipient to donor allotype following organ transplantation has demonstrated the synthetic sites of several complement proteins, but in the case of C7 this was not possible until recently. A novel C7 polymorphism (C7 M/N) has been described based on the reactivity with the monoclonal antibody WU 4-15 which identifies in allotype of C7 (C7 M). Bone marrow and hepatic C7 production was quantified in bone marrow transplant and liver transplant recipients, respectively, where a mismatch for the C7 allotypes distinguished by the monoclonal antibody had occurred. In the bone marrow transplant group, one informative transplant was identified and donor-derived C7 was detected by enzyme-linked immunosorbent assay. It contributed to 18-27% of the total circulating C7 during the post-transplant phase and was increased during episodes of inflammation. In the liver transplant group, the hepatic contribution to the C7 levels were 30% and 52%, respectively, in two patients identified prospectively. A further three informative liver transplant patients were identified retrospectively and in these individuals, 56-62% of the circulating C7 was liver-derived. This study demonstrates that the majority of the circulating C7 is derived from the liver and bone marrow with a lesser contribution from other sources. These findings provide further support for the concept that locally secreted complement proteins have an important role in inflammation.

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“…These preparations were designat ed NHS-EGTAand NHS-EDTA. Another part of the serum pool was heated at + 50 °C for 20 min to inactivate the alternative pathway of complement activation (18). This preparation was designated NHS-50°.…”

Section: Preparation O F Seramentioning

confidence: 99%

Dialysis Granulocytopenia Is Preceded by an Increased Surface Expression of the Adhesion-Promoting Glucoprotein Mac-1

Lundahl

Hed²,

Jacobson³

1992

Nephron

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We studied the expression of Mac-1 on granulocytes (flow cytometry) from 9 patients (27 examinations) during hemodialysis with cuprophane membranes (CuM). Samples were drawn before dialysis and from the arterial and venous lines at 5,15 and 180 min. Granulocytopenia was most pronounced after 15 min of treatment. Mac-1 expression on granulocytes increased during dialysis, and a pronounced enhancement occurred across the dialyzer. Mac-1 expression on granulocytes increased 116% across the dialyzer at 5 min, and the degree of Mac-1 mobilization at 5 min correlated with the degree of subsequent granulocytopenia at 15 min. In in vitro experiments, granulocytes from healthy blood donors were incubated with plasma drawn from the arterial and venous lines at 5 min. Plasma drawn from the venous line at 5 min had a greater ability to mobilize Mac-1 than plasma from the arterial line (p < 0.002). This difference correlated with the degree of granulocytopenia at 15 min (r = 0.76, p = 0.01). Pieces of a washed CuM were incubated in normal human serum (NHS) preparations for different times. Inactivation of the alternative pathway of complement activation (NHS-50°) did not alter the generation of Mac-1-mobilizating capacity compared to NHS. In contrast, inactivation of the classical pathway (NHS-EGTA) decreased the early but not the late generation of Mac-1-mobilizating capacity. Our results indicate that the early mobilization and not the absolute expression of Mac-1 correlates with granulocytopenia, and that sera in vitro attain Mac-1-mobilizating capacity more rapidly when the classical pathway of complement activation is intact.

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Human Alveolar Macrophages Synthesize Active Complement Components C6, C7, and C8 in Vitro

Cited by 22 publications

References 7 publications

Reduction of Neutrophil Activation by Vitamin E Modified Dialyzer Membranes

Reduction of Neutrophil Activation by Vitamin E Modified Dialyzer Membranes

Organ‐specific contribution to circulating C7 levels by the bone marrow and liver in humans

Dialysis Granulocytopenia Is Preceded by an Increased Surface Expression of the Adhesion-Promoting Glucoprotein Mac-1

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