Detection of soluble alpha1 integrin in human serum.
An enzyme-linked immunosorbent assay (ELISA) for the detection and quantitation of soluble alpha1beta1 integrins (salpha1) in human serum samples was developed. Solid phase-bound anti-alpha1 integrin monoclonal antibody (mAb) TS2/7 was used to capture salpha1, and mAb 1B3.1 was used to detect the immobilized integrin. An extract of human placenta (PE) containing 340 ng/mL of VLA-1 molecules served as a positive control, and serum samples from normal donors and patients were assayed. Optimal binding of anti-alpha1 integrin mAb 1B3.1, expressed as specific optical density (OD), was obtained when a 5 microng/mL solution of anti-alpha1 integrin "capture" mAb TS2/7 was immobilized to the wells and the PE was added. Solutions of albumin or collagen, in contrast, did not result in binding, confirming the specificity of the assay for sal. Furthermore, the specific OD of the wells correlated directly with the concentration of PE. A concentration of salpha1 above that of a 1:100 dilution of PE--that is, >3.4 ng/mL of integrin, in which the intra-assay correlation of variance was <5.7%, was found in 5 of 8, 3 of 8, and 6 of 9 serum samples from normal individuals, patients with connective tissue diseases (CTD), and patients with liver diseases (LD), respectively. These results suggest, for the first time, that salpha1 are present in healthy and diseased human serum.
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Department of Medicine, Chaim Sheba Medical Center, Sackler School of Medicine, Israel.
Weiss
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Doolman
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Book
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Sela
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D000328:Adult; D000418:Albumins / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000097:blood* / Q000276:immunology; D003094:Collagen / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D039423:Integrin alpha1; D039222:Integrin alpha1beta1; D016023:Integrins / Q000032:analysis / Q000097:blood* / Q000276:immunology; D008107:Liver Diseases / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D010920:Placenta / Q000502:physiology; D011247:Pregnancy; D012595:Scleroderma, Systemic / Q000097:blood; D012680:Sensitivity and Specificity; D014020:Tissue Extracts / Q000737:chemistry
D000418:Albumins; D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D039423:Integrin alpha1; D039222:Integrin alpha1beta1; D016023:Integrins; D014020:Tissue Extracts; D003094:Collagen