title: Autodisplay of the La/SSB protein on LPS-free E. coli for the diagnosis of Sjögren's syndrome.
abstract: The objective of this study was to present an immunoassay for the diagnosis of Sjögren's syndrome based on the autodisplayed La/SSB protein on the outer membrane of intact E. coli (strain UT-5600) and LPS-free E. coli (ClearColi™). As the first step, an autodisplay vector (pCK002) was transfected into intact E. coli and LPS-free E. coli for comparison of efficiency of autdisplay of La/SSB. The maximal level of La/SSB expression was estimated to be similar for LPS-free E. coli and intact E. coli at different optimal induction periods. Intact E. coli was found to grow twofold faster than LPS-free E. coli, and the maximal level of expression for LPS-free E. coli was obtained with a longer induction period. When the zeta potential was measured, both intact E. coli and LPS-free E. coli showed negative values, and the autodisplay of negatively charged La/SSB protein (pI<7) on the outer membrane of intact E. coli and LPS-free E. coli resulted in a slight change in zeta potential values. E. coli with autodisplayed La/SSB protein was used for an immunoassay of anti-La/SSB antibodies for the diagnosis of Sjögren's syndrome. The surface of E. coli with the autodisplayed antigen was modified with rabbit serum and papain to prevent false positive signals because of nonspecific binding of unrelated antibodies from human serum. LPS-free E. coli with autodisplayed La/SSB protein yielded sensitivity and selectivity of 81.6% and 78.6%, respectively. The Bland-Altman test showed that the immunoassays based on LPS-free E. coli and intact E. coli with autodisplayed La/SSB protein were statistically equivalent to a clinical immunoassay for detection of anti-La/SSB antibodies (confidence coefficient 95%).
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seo-dae-mun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Gu
authors.initials: G
authors.lastname: Yoo
authors.affiliation: Institute of Pharmaceutical and Medical Chemistry, University of Muenster, Muenster, Germany.
authors.forename: Carina
authors.initials: C
authors.lastname: Dilkaute
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seo-dae-mun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Bong
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seo-dae-mun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Hyun-Woo
authors.initials: HW
authors.lastname: Song
authors.affiliation: College of Life Science and Bioengineering, Incheon National University, Incheon, Republic of Korea.
authors.forename: Misu
authors.initials: M
authors.lastname: Lee
authors.affiliation: Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea.
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kang
authors.affiliation: Institute of Pharmaceutical and Medical Chemistry, University of Muenster, Muenster, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Jose
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seo-dae-mun-gu, Seoul 120-749, Republic of Korea. Electronic address: jcpyun@yonsei.ac.kr.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Pyun
mesh_terms: D000818:Animals; D000974:Antibodies, Antinuclear / Q000097:blood*; D001324:Autoantigens / Q000235:genetics; D061505:Cell Surface Display Techniques / Q000379:methods; D004926:Escherichia coli / Q000235:genetics / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007159:Immunologic Tests / Q000379:methods; D008070:Lipopolysaccharides / Q000276:immunology; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000276:immunology; D011817:Rabbits; D012261:Ribonucleoproteins / Q000235:genetics; D012859:Sjogren's Syndrome / Q000175:diagnosis* / Q000276:immunology*; D000097585:SS-B Antigen
chemical_list: D000974:Antibodies, Antinuclear; D001324:Autoantigens; D008070:Lipopolysaccharides; D012261:Ribonucleoproteins; D000097585:SS-B Antigen; C035357:SS-B antibodies
keywords: Autodisplay; LPS-free E. coli; La/SSB; Lipopolysaccharide; Sjögren’s syndrome