Formation and properties of C1‐inhibitor polymers

Patston, Philip A.; Hauert, J; Michaud, Marilynn; Schapira, Marc

doi:10.1016/0014-5793(95)00694-5

Cited by 37 publications

(3 citation statements)

References 25 publications

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“…A previous study by Nielsen (33) showed that even large excess of C1-INH had no effect on the activation of C1 by immune complexes. However, the C1-INH preparation used in that work differed from the C1-INH available for us (34, 35). Therefore, we set up a method to detect the specific activation of C1 induced by heat-aggregated gamma globulins.…”

Section: Discussionmentioning

confidence: 99%

A New Tool for Complement Research: In vitro Reconstituted Human Classical Complement Pathway

et al. 2018

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The complement, as part of the innate immune system, represents the first line of defense against Gram-negative bacteria invading the bloodstream. The complement system is a zymogen cascade that ultimately assemble into the so-called membrane attack complex (MAC), which lyses Gram-negative bacteria upon insertion into the outer membrane. Traditionally, serum has been used as complement source, for example to study the bactericidal activity of monoclonal antibodies or antibodies raised upon vaccination. Due to the significant donor to donor variability, as well as susceptibility of complement factors to handling and storage conditions, assay reproducibility using human serum is low. Moreover, the presence of pre-existing antibodies and antimicrobial compounds are confounding factors. To remove antibodies from human serum, we applied κ/λ-light chain specific affinity chromatography, however the method severely reduced the complement activity due to the depletion of complement components. Therefore, we attempted to reconstitute human complement—namely the alternative (rAP) and the classical (rCP) pathways—from purified complement factors. We found that adding C1-inhibitor to the mixture was essential to maintain a stable and functional C1 and thus to generate an active rCP. We further confirmed the functionality of the rCP by testing the complement-dependent bactericidal activity of a human monoclonal antibody, A1124 against an E. coli clinical isolate belonging to the ST131 clonal complex, and that of a polyclonal IVIg against a laboratory E. coli strain (MG1655) not expressing LPS O-antigen and capsule. Although the alternative pathway did not have any bactericidal activity by itself, it enhanced MAC deposition induced by rCP and increased the overall bactericidal activity against the ST131 E. coli strain. In conclusion, we report for the first time the successful in vitro reconstitution of the classical pathway of the human complement to establish a serum-free, complement dependent bactericidal assay. This system offers high level of standardization and could support the study of the complement in different research fields.

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Section: Discussionmentioning

confidence: 99%

A New Tool for Complement Research: In vitro Reconstituted Human Classical Complement Pathway

et al. 2018

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“…An unwanted consequence of this thermodynamically favored, conformational lability, however, is the tendency of serpins to use the same properties to form polymers through loop-sheet insertion mechanisms involving the loop of one molecule and a β-sheet of another. This can readily be seen with most serpins by heating at ∼50−60 °C for a few minutes followed by analysis of the products on a nondenaturing gel …”

Section: 4 Serpin Polymerizationmentioning

confidence: 99%

Serpin Structure, Mechanism, and Function

2002

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“…It has been reported that serpin can form stable dimers in vitro in the presence of SDS 40, 41, and dimer formation may be enhanced by low pH, denaturing agents, and heating 42, 43, 44. Although the aforementioned factors may affect dimer formation, in our experiments it was observed that dimerization would be produced before the SDS/PAGE procedure.…”

Section: Discussionmentioning

confidence: 49%

MSP22.8 is a protease inhibitor‐like protein involved in shell mineralization in the edible mussel Mytilus galloprovincialis

Calvo-Iglesias

Pérez-Estévez²,

González-Fernández

2017

FEBS Open Bio

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The mussel shell protein 22.8 (MSP22.8) is recognized by a monoclonal antibody (M22.8) directed against larvae of the mussel Mytilus galloprovincialis. After being secreted by cells of the mantle‐edge epithelium into the extrapallial (EP) space (the gap between the mantle and the shell), the protein is detected in the extrapallial fluid (EPF) and EP hemocytes and finally becomes part of the shell matrix framework in adult specimens of M. galloprovincialis. In the work described here, we show how MSP22.8 is detected in EPF samples from different species of mussels (M. galloprovincialis, Mytilus edulis, and Xenostrobus securis), and also as a shell matrix protein in M. galloprovincialis, Mytilus chilensis, and Perna canaliculus. A multistep purification strategy was employed to isolate the protein from the EPF, which was then analyzed by mass spectrometry in order to identify it. The results indicate that MSP22.8 is a serpin‐like protein that has great similarity with the protease inhibitor‐like protein‐B1, reported previously for Mytilus coruscus. We suggest that MSP22.8 is part of a system offering protection from proteolysis during biomineralization and is also part of the innate immune system in mussels.

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Formation and properties of C1‐inhibitor polymers

Cited by 37 publications

References 25 publications

A New Tool for Complement Research: In vitro Reconstituted Human Classical Complement Pathway

A New Tool for Complement Research: In vitro Reconstituted Human Classical Complement Pathway

Serpin Structure, Mechanism, and Function

MSP22.8 is a protease inhibitor‐like protein involved in shell mineralization in the edible mussel Mytilus galloprovincialis

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