Premium
In vivo inhibition of antiphospholipid antibody‐induced pathogenicity utilizing the antigenic target peptide domain I of β 2 ‐glycoprotein I: proof of concept
Author(s) -
IOANNOU Y.,
ROMAYPENABAD Z.,
PERICLEOUS C.,
GILES I.,
PAPALARDO E.,
VARGAS G.,
SHILAGARD T.,
LATCHMAN D. S.,
ISENBERG D. A.,
RAHMAN A.,
PIERANGELI S.
Publication year - 2009
Publication title -
journal of thrombosis and haemostasis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.947
H-Index - 178
eISSN - 1538-7836
pISSN - 1538-7933
DOI - 10.1111/j.1538-7836.2009.03316.x
Subject(s) - in vivo , antiphospholipid syndrome , microbiology and biotechnology , antibody , recombinant dna , epitope , antigen , chemistry , immunology , peptide , biology , biochemistry , gene
Summary. Objectives: In the antiphospholipid syndrome (APS), the immunodominant epitope for the majority of circulating pathogenic antiphospholipid antibodies (aPLs) is the N‐terminal domain I (DI) of β 2 ‐glycoprotein I. We have previously shown that recombinant DI inhibits the binding of aPLs in fluid phase to immobilized native antigen, and that this inhibition is greater with the DI(D8S/D9G) mutant and absent with the DI(R39S) mutant. Hence, we hypothesized that DI and DI(D8S/D9G) would inhibit aPL‐induced pathogenicity in vivo . Methods: C57BL/6 mice ( n = 5, each group) were injected with purified IgG derived from APS patients (IgG‐APS, 500 μg) or IgG from normal healthy serum (IgG‐NHS) and either recombinant DI, DI(R39S), DI(D8S/D9G), or an irrelevant control peptide (at 10–40 μg). Outcome variables measured were femoral vein thrombus dynamics in treated and control groups following standardized vessel injury, expression of vascular cell adhesion molecule‐1 (VCAM‐1) on the aortic endothelial surface, and tissue factor (TF) activity in murine macrophages. Results: IgG‐APS significantly increased thrombus size as compared with IgG‐NHS. The IgG‐APS thrombus enhancement effect was abolished in mice pretreated with recombinant DI ( P ≤ 0.0001) and DI(D8S/D9G) ( P ≤ 0.0001), but not in those treated with DI(R39S) or control peptide. This inhibitory effect by DI was dose‐dependent, and at lower doses DI(D8S/D9G) was a more potent inhibitor of thrombosis than wild‐type DI ( P ≤ 0.01). DI also inhibited IgG‐APS induction of VCAM‐1 on the aortic endothelial surface and TF production by murine macrophages. Conclusion: Our findings in this proof‐of‐concept study support the development of recombinant DI or the novel variant DI(D8S/D9G) as a potential future therapeutic agent for APS.