Dataset Information
Variability in exposure of epitope G40-R43 of domain i in commercial anti-beta2-glycoprotein I IgG ELISAs.
Ontology highlight
ABSTRACT: Background
A major problem for diagnosing the antiphospholipid syndrome (APS) is the high variability between commercial anti-?2glycoprotein I (?2GPI) assays. Predominantly antibodies reactive against cryptic epitope Glycine40-Arginine43 (G40-R43) in domain I are associated with an increased risk for thrombosis. Upon interaction with anionic surfaces ?2GPI opens up, thereby exposing G40-R43.Objectives
To examine whether suboptimal exposure of epitope G40-R43 explains the variations in results observed between commercial assays.Methods
Two patient-derived monoclonal antibodies were tested on neutral versus anionic plates. Antibody P1-117 reacts with G40-R43 in the open conformation while P2-6 recognizes ?2GPI irrespective of its conformation. These antibodies were tested in commercial anti-?2GPI assays (A-E).Results
In assay A, both antibodies showed equal reactivity towards ?2GPI, indicating that all the ?2GPI exposes G40-R43. In other assays P1-117 displayed lower reactivity than P2-6, demonstrating reduced G40-R43 availability. To exclude influences of other assay features, reactivity was re-examined on plates of assay A and B using the protocol/reagents from each assay. In all combinations, reactivity of both antibodies on a plate was comparable to results obtained with its own protocol/reagents, suggesting that the coating, rather than other assay components, accounts for the observed differences. In two patient cohorts we demonstrated that a number of domain I-reactive samples are missed in assays characterized by a decreased exposure of epitope G40-R43.Conclusions
Exposure of epitope G40-R43 on ?2GPI is highly variable between commercial anti-?2GPI assays. As a consequence, patients can be falsely assigned negative in assays characterized by a reduced exposure of G40-R43.
SUBMITTER: Pelkmans L
PROVIDER: S-EPMC3741166 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
Publications
Variability in exposure of epitope G40-R43 of domain i in commercial anti-beta2-glycoprotein I IgG ELISAs.
PloS one 20130812 8
<h4>Background</h4>A major problem for diagnosing the antiphospholipid syndrome (APS) is the high variability between commercial anti-β2glycoprotein I (β2GPI) assays. Predominantly antibodies reactive against cryptic epitope Glycine40-Arginine43 (G40-R43) in domain I are associated with an increased risk for thrombosis. Upon interaction with anionic surfaces β2GPI opens up, thereby exposing G40-R43.<h4>Objectives</h4>To examine whether suboptimal exposure of epitope G40-R43 explains the variatio ...[more]