Cloning and expression of beta 2-glycoprotein 1 recognized by antiphospholipid antibodies and its clinical investigation.
OBJECTIVE
To investigate cloning and expression of beta 2-glycoprotein 1 (beta 2GP1) recognized by antiphospholipid antibodies and to study the clinical significance of anti-beta 2GP1 antibodies in patients with autoimmune disease.


METHODS
By using reverse transcription-PCR method, two kinds of expression plasmid which expressed beta 2GP1 and the fifth domain of beta 2-glycoprotein 1 (beta 2GP1-D5) proteins respectively were constructed in this study. Their antigenic activities were identified by immunoblots using rabbit anti-beta 2GP1 antibodies. Anti-r beta 2GP1 and anti-r beta 2GP1-D5 antibodies in the 112 patents were detected by ELISA using r beta 2GP1 and r beta 2GP1-D5 as coating antigens.


RESULTS
A significant correlation in statistics (r = 0.667, P < 0.01) between the levels of anti-r beta 2GP1 and anticardiolipin antibodies (aCL) was found. The presence of anti-r beta 2GP1 antibodies was associated with an increased frequency of history of thrombosis and/or recurrent abortion. Anti-r beta 2GP1 assay provided better specificity than conventional aCL assay. The binding of anti-r beta 2GP1 from the sera of patients with antiphospholipid syndrome (APS) to r beta 2GP1 was inhibited by r beta 2GP1-D5. Meanwhile, of 28 patients who had positive anti-r beta 2GP1 antibodies in sera, 27 (96.4%) had positive anti-r beta 2GP1-D5 antibodies.


CONCLUSIONS
It is indicated that antigenic epitope of beta 2 GP1 might be located in its fifth domain. Detection of anti-r beta 2GP1 antibodies may be of potential value for evaluating the risk of thrombosis and/or other APS associated symptom.
Chen
S
S
Department of Clinical Immunology & Rheumatology, Renji Hospital, Shanghai Second Medical University, Shanghai 200001, China.
Yang
C
C
Shen
N
N
Xue
F
F
D017152:Antibodies, Antiphospholipid / Q000276:immunology*; D016736:Antiphospholipid Syndrome / Q000175:diagnosis / Q000209:etiology; D003001:Cloning, Molecular; D000939:Epitopes; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000276:immunology; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology; D053482:beta 2-Glycoprotein I
D017152:Antibodies, Antiphospholipid; D000939:Epitopes; D006023:Glycoproteins; D011993:Recombinant Fusion Proteins; D053482:beta 2-Glycoprotein I