α1-Antichymotrypsin Present in Therapeutic C1-Inhibitor Products Competes with Selectin-Sialyl LewisX Interaction.
Publisher DOI
PubMed ID
30453343
Abstract
BACKGROUND
C1-inhibitor (C1-inh) therapeutics can reduce neutrophil activity in various inflammatory conditions. This 'novel' anti-inflammatory effect of C1-inh is attributed to the tetrasaccharide sialyl Lewis (SLe) present on its glycans. Via SLe, C1-inh is suggested to interact with selectins on inflamed endothelium and prevent neutrophil rolling. However, C1-inh products contain plasma glycoprotein α1-antichymotrypsin (ACT) as a co-purified protein impurity.
OBJECTIVE
This article investigates the contribution of ACT to the effects observed with C1-inh.
MATERIALS AND METHODS
We have separated C1-inh and ACT from a therapeutic C1-inh preparation and investigated the influence of these proteins on SLe-selectin interactions in a specific in vitro model, which makes use of rolling of SLe-coated beads on immobilized E-selectin.
RESULTS
We find that ACT and not C1-inh, shows a clear sialic acid-dependent interference in SLe-selectin interactions, at concentrations present in C1-inh therapeutics. Furthermore, we do not find any evidence of SLe on C1-inh using either Western blotting with anti-SLe antibodies (CSLEX1 and KM93) or by mass spectrometric analysis of glycans. C1-inh reacts weakly to antibody HECA-452, which detects a broad range of selectin ligands, but ACT gives a much stronger signal, suggesting the presence of a selectin ligand on ACT.
CONCLUSION
The 'novel' anti-inflammatory effects of C1-inh are unlikely due to SLe on C1-inh and can in fact be due to SLe-like glycans on ACT, present in C1-inh products. In view of our results, it is important to assess the role of ACT in vivo and revisit past studies performed with commercial C1-inh.
C1-inhibitor (C1-inh) therapeutics can reduce neutrophil activity in various inflammatory conditions. This 'novel' anti-inflammatory effect of C1-inh is attributed to the tetrasaccharide sialyl Lewis (SLe) present on its glycans. Via SLe, C1-inh is suggested to interact with selectins on inflamed endothelium and prevent neutrophil rolling. However, C1-inh products contain plasma glycoprotein α1-antichymotrypsin (ACT) as a co-purified protein impurity.
OBJECTIVE
This article investigates the contribution of ACT to the effects observed with C1-inh.
MATERIALS AND METHODS
We have separated C1-inh and ACT from a therapeutic C1-inh preparation and investigated the influence of these proteins on SLe-selectin interactions in a specific in vitro model, which makes use of rolling of SLe-coated beads on immobilized E-selectin.
RESULTS
We find that ACT and not C1-inh, shows a clear sialic acid-dependent interference in SLe-selectin interactions, at concentrations present in C1-inh therapeutics. Furthermore, we do not find any evidence of SLe on C1-inh using either Western blotting with anti-SLe antibodies (CSLEX1 and KM93) or by mass spectrometric analysis of glycans. C1-inh reacts weakly to antibody HECA-452, which detects a broad range of selectin ligands, but ACT gives a much stronger signal, suggesting the presence of a selectin ligand on ACT.
CONCLUSION
The 'novel' anti-inflammatory effects of C1-inh are unlikely due to SLe on C1-inh and can in fact be due to SLe-like glycans on ACT, present in C1-inh products. In view of our results, it is important to assess the role of ACT in vivo and revisit past studies performed with commercial C1-inh.
Date Issued
2018-12
Publication Type
Article
Subject(s)
Language(s)
en
Author(s)
Engel, Ruchira | |
Delvasto-Nuñez, Laura | |
Roem, Dorina | |
van Mierlo, Gerard | |
Holst, Stephanie | |
Hipgrave Ederveen, Agnes L | |
van Buul, Jaap D | |
Wuhrer, Manfred | |
Wouters, Diana |
Additional Credits
Journal
Thrombosis and haemostasis
Publisher
Thieme
ISSN
2567-689X
Access(Rights)
restricted