DiaPharma Group, Inc.

For research use only. Not for use in diagnostic procedures.

Sandwich ELISA method for the evaluation of IgG isotype autoantibodies targeted to annexin V, on human plasma or serum. The assay is designed with highly purified human recombinant annexin V, obtained with non-denaturating methods, for autoantibody immunocapture. These latter are then revealed with a goat antibody specific for IgG Fcg fragments, and labeled with peroxidase.

Structure & Mechanism of Action

Annexin V is a calcium-dependent protein with anticoagulant properties. Auto-antibodies to Annexin V are usually not found in the normal population, though they can be present at low concentrations during pregnancy.

Significance

The presence of Annexin V auto-antibodies at high concentrations can be associated with recurrent spontaneous abortion (and might therefore be considered a risk factor), or with some types of the Anti-Phospholipid Syndrome. Auto-antibodies to Annexin V are also linked with excess of apoptosis. Research has found that patients with SLE frequently have some auto-antibodies to b2GPI, prothrombin, protein C, protein S, and annexin V. Thrombotic complications in SLE may depend on the antigenic specificities of these antibodies, alone or in combination.

Assay Principle

Highly purified human recombinant Annexin V are coated onto a microplate. The diluted plasma sample or biological fluid is added to the well of the coated plate. When present, anti-Annexin V auto-antibodies bind to immobilised Annexin V. Following a washing step, bound auto-antibodies of the IgG or IgM isotype are revealed with a goat anti-human IgG (Fcg specific) or goat anti-human IgM (Fcm specific)-peroxidase conjugate, which react specifically with the desired isotype. Following a new washing step, OPD substrate in the presence of H2O2 is added and color develops. The color developed is directly proportional to the amount of anti-Annexin V auto-antibodies of the IgG or IgM isotype present in the tested sample.

Assay Features

· Complete, ready to use, & optimised - kit contains calibrators and controls
· For isotyping auto-antibodies to phospholipids cofactor Annexin V IgG or IgM
· Well-defined cut-off
· Fast, easy to perform, reliable and reproducible
· High sensitivity, specificity, and reactivity
· Native structure of auto-antigens are preserved
· Low background noise

Can be combined with a full range of innovative assays for testing auto-antibodies to phospholipids cofactors, including anti-b2GP1, anti-Prothrombin, and anti-Protein S.