Estimation of plasma beta-2-glycoprotein levels by competitive ELISA

Krishnakumar Balasubramanian, Jerald J. Killion, Alan J. Schroit

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Beta-2-glycoprotein I (β2GPI), a 50-kDA serum glycoprotein that binds negatively charged phospholipids plays a role in coagulation, thrombosis, and the clearance of phosphatidylserine expressing cells. Because of its recently recognized role in several autoimmune responses, we have developed a method that quantifies plasma β2GPI levels by using a competitive ELISA assay. When combined with data from a standard ELISA, this method determines the concentration of free β2GPI and the fraction of antibody-bound β2GPI thereby facilitating quantification of total antigen in individuals with autoimmune antibodies. Standard competitive inhibition ELISA was compared with this method, which uses known amounts of standard β2GPI added to the plasma as an internal standard. Identical results were obtained with both methods for plasma samples from normal individuals that did not contain blocking antibodies. Analysis of plasma from antiphospholipid syndrome patients (patients with autoantibodies to β2GPI) by the internal standard method, however, resulted in significantly lower apparent β2GPI levels indicating that a substantial fraction of the plasma β2GPI was bound by antibody.

Original languageEnglish (US)
Pages (from-to)91-97
Number of pages7
JournalThrombosis Research
Volume92
Issue number2
DOIs
StatePublished - Oct 15 1998

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Glycoproteins
Enzyme-Linked Immunosorbent Assay
Antibodies
beta 2-Glycoprotein I
Blocking Antibodies
Antiphospholipid Syndrome
Phosphatidylserines
Autoimmunity
Autoantibodies
Phospholipids
Thrombosis
Antigens
Serum

Keywords

  • Beta-2-glycoprotein I
  • ELISA
  • Plasma

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Hematology

Cite this

Estimation of plasma beta-2-glycoprotein levels by competitive ELISA. / Balasubramanian, Krishnakumar; Killion, Jerald J.; Schroit, Alan J.

In: Thrombosis Research, Vol. 92, No. 2, 15.10.1998, p. 91-97.

Research output: Contribution to journalArticle

Balasubramanian, Krishnakumar ; Killion, Jerald J. ; Schroit, Alan J. / Estimation of plasma beta-2-glycoprotein levels by competitive ELISA. In: Thrombosis Research. 1998 ; Vol. 92, No. 2. pp. 91-97.
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