Occurence of antibodies against chlamydial lipopolysaccharide in human sera as measured by ELISA using an artificial glycoconjugate antigen

Abstract

An artificial glycoconjugate containing, as a ligand, the deacylated carbohydrate backbone of a recombinant Chlamydia-specific lipopolysaccharide was used as a solid-phase antigen in ELISA to measure antibodies against chlamydial LPS. The specificity and reproducibility of the assay was shown by using a panel of prototype monoclonal antibodies representing the spectrum of antibodies also occurring in patient sera. These mAbs recognized Chlamydia-specific epitopes [alpha 2-->8-linked disaccharide of 3-deoxy-D-manno-octulosonic acid (Kdo) or the trisaccharide alpha Kdo-(2-->8)-alpha Kdo-(2-->4)-alpha Kdo] or those shared between chlamydial and Re-type LPS (alpha Kdo, alpha 2-->4-linked Kdo disaccharide). The assay was used to measure IgG, IgA and IgM antibodies against chlamydial LPS in patients with genital or respiratory tract infections. In comparison to the results obtained with sera from blood donors, it became evident that both types of infection result in significant changes in the profile of LPS antibodies.

Identification of a Cross-reactive Epitope Widely Present in Lipopolysaccharide from Enterobacteria and Recognized by the Cross-protective Monoclonal Antibody WN1 222-5

“…ELISA with J-5 Core Oligosaccharides-Aiming at the identification of the minimal epitope required for the binding of WN1 222-5, we have conjugated each of the oligosaccharides obtained from E. coli J-5 LPS and the newly prepared octasaccharide 1 P 3 to BSA using glutardialdehyde coupling (20). The octasaccharide 1 P 3 conjugate was included to elucidate the importance of phosphate substitution and side chain heptose substitution with GlcpN for antigen binding by WN1 222-5.…”

“…Neoglycoconjugates-Neoglycoconjugates of deacylated oligosaccharides were prepared as described (20). Briefly, ligands (2.5 mg) were dissolved in 200 l of 50 mM carbonate buffer, pH 9.2; glutardialdehyde (25%, electron microscopy grade; Merck) was added (1% final concentration); and the sample was stirred for 4 h at 25°C under N 2 atmo-FIG.…”

C-Reactive Protein in Healthy Subjects: Associations With Obesity, Insulin Resistance, and Endothelial Dysfunction

“…C pneumoniae IgG antibody titers were determined by ELISA according to a published method. 33 Cytomegalovirus (CMV) IgG titers were determined using a standard microtiter complement fixation assay, using in-house CMV antigen prepared from the AD169 strain of CMV. These assays were performed in the Departments of Microbiology and Virology, UCL Hospitals, London.…”

Association of Seropositivity for Antibody to Chlamydia-Specific Lipopolysaccharide and Coronary Artery Disease in Japanese Men

“…In patients who had emergency CAG, serum samples for measurements of antibodies to Chlamydia were obtained at the beginning of CAG, and serum samples for lipid profiles were obtained after overnight fasting. The levels of IgA and IgG antibodies to Chlamydia-specific LPS were measured by ELISA kits (Medac, Hamburg, Germany), as described previously, [31][32][33] which are based on a chemically pure recombinant LPS containing a genusspecific epitope of Chlamydia spp. 33 The lower limit of a positive control was defined as an optical density (OD) >0.60, and the upper limit of a negative control was defined as an OD <0.22.…”

“…The levels of IgA and IgG antibodies to Chlamydia-specific LPS were measured by ELISA kits (Medac, Hamburg, Germany), as described previously, [31][32][33] which are based on a chemically pure recombinant LPS containing a genusspecific epitope of Chlamydia spp. 33 The lower limit of a positive control was defined as an optical density (OD) >0.60, and the upper limit of a negative control was defined as an OD <0.22. The indices of antibodies were determined by the following formula, index = (serum sample OD -blank OD) /(negative control OD-blank OD+ 0.32).…”