Chemical, biological, and immunochemical properties of the Chlamydia psittaci lipopolysaccharide

Abstract

The lipopolysaccharide (LPS) of Chlamydia psittaci was extracted from yolk sac-grown elementary bodies, purified, and characterized chemically, immunochemically, and biologically. The LPS contained Dgalactosamine, D-glucosamine, phosphorus, long-chain fatty acids, and 3-deoxy-D-manno-2-octulosonic acid in the molar ratio of approximately 1:2:2:6:5. The antigenic properties of the isolated LPS were compared with those of the LPS from Chiamydia trachomatis and Salmonella minnesota Re by the passive hemolysis and passive hemolysis inhibition tests, absorption, hydrolysis kinetics, and Western blot analysis with rabbit polyclonal antisera against chlamydiae and with a mouse monoclonal antibody recognizing a genus-specific epitope of chlamydial LPS. Two antigenic determinants were identified, one of which was chlamydia specific and the other of which was cross-reactive with Re LPS. Both determinants were destroyed during acid hydrolysis, whereby a third antigen specificity was exposed which was indistinguishable from the lipid A antigenicity. In rabbit polyclonal antisera prepared against Formalin-killed elementary bodies or detergent-solubilized membranes, two antibody specificities were differentiated. One of these was chlamydia specific, and the other was cross-reactive with Re LPS. The LPS of C. psittaci was inactive within typical endotoxin parameters (lethal toxicity, pyrogenicity, local Shwartzman reactivity); it was, however, active in some in vitro assays, such as those testing for mouse B-cell mitogenicity and the induction of prostaglandin E2 in mouse peritoneal macrophages.

Endotoxic activity and chemical structure of lipopolysaccharides from Chlamydia trachomatis serotypes E and L2 and Chlamydophila psittaci 6BC

“…One should keep in mind that even minor contamination with proteins, lipoproteins or nucleic acids may be relevant in the sensitive assays available today. Nevertheless, there is good evidence from our group [10] and others [11] that chlamydial LPS is less active than typical enterobacterial LPS in classical endotoxin assays. When we decided to investigate the biological activity of chlamydial LPS in more detail we wanted to base this study on preparations whose structures had been characterized fully.…”

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

“…Thus, synthetic peptides have been used recently to determine antibodies against the major outer membrane protein in patients suffering from trachoma [12]. Our group has accumulated knowledge on the chemical [19,20,22] and antigenic [15,18,19,24] structure of chlamydial LPS, and has developed reagents suitable to be used in simple antibody-detection assays [26,32,33,35]. In particular, the synthesis of artificial glycoconjugates with chemically defined carbohydrate ligands allowed us to determine the epitope specificities of poly-and monoclonal antibodies [15,26].…”

“…It has been shown to be a multifunctional glycosyl-transferase catalyzing three glycosylation steps [21] leading to the formation of a trisaccharide of 3-deoxy-o-manno-octulosonic acid (Kdo) of the sequence aKdo-(2 8)-aKdo-(2-~ 4)-c~Kdo [19,20,22]. The a2 ~ 4linked disaccharide portion of the trisaccharide is identical to that of enterobacterial Re-mutants [23] and forms the molecular basis for cross-reactions between chlamydial and Re-type LPS [15,24,25]. In addition, we have shown that synthetic artificial glycoconjugate antigens containing this epitope bind specifically mAbs against chlamydial LPS [22,26].…”

The Structures of Oligosaccharide Bisphosphates Isolated from the Lipopolysaccharide of a Recombinant Escherichia coli Strain Expressing the Gene gseA [3-deoxy-d-manno-Octulopyranosonic Acid (Kdo) Transferase] of Chlamydia psittaci 6BC

“…Three fractions were obtained, eluting between sodium acetate concentrations of 255 -273 mM (tetrasaccharide bisphosphate l), 318-347 mM (mixture of two pentasaccharide bisphosphates 2 and 3), and 393-420 mM (hexasaccharide bisphosphate 4). These compounds were desalted by gel-permeation chromatography and lyophilised (tetrasaccharide bisphosphate: 48.3 mg, 19.6mg GlcN, 7.2% total LPS; mixture of pentasaccharide bisphosphates: 124.2 mg, 41.5 mg GlcN, 15.2% total LPS; hexasaccharide bisphosphate: 72.7 mg, 19.7 mg GlcN, 7.2% total LPS). Analytical HPAE revealed one compound each for the tetrasaccharide and hexasaccharide bisphosphate, and two compounds for the pentasaccharide bisphosphate mixture.…”