Characterization of the Salmonella Typhimurium core oligosaccharide and its reducing end 3-deoxy-d-manno-oct-2-ulosonic acid used for conjugate vaccine production

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2019-2020

This review is the tenth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2020. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. The review is basically divided into three sections: (1) general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, quantification and the use of arrays. (2) Applications to various structural types such as oligo- and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals, and (3) other areas such as medicine, industrial processes and glycan synthesis where MALDI is extensively used. Much of the material relating to applications is presented in tabular form. The reported work shows increasing use of incorporation of new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented nearly 40 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show little sign of diminishing.

Molecular properties and ligand specificity of zebrafish intelectin-2

Intelectins are immune lectins expressed in chordates, including several fish species, in which intelectins are known to be upregulated upon infection. However, the basic biochemical properties and bacteria binding specificities of several fish intelectins are not well studied. We focus our investigation on zebrafish intelectin-2 (DrIntL-2) that is predominantly expressed in the gastrointestinal tract. The disulfide-linked oligomeric state and the cysteine responsible for intermolecular disulfide bonds are identified. DrIntL-2 is a globular particle of around 30 nm. In addition to the typical exocyclic 1,2-diol ligands, DrIntL-2 binds β-1,3-glucan and recognizes Salmonella typhimurium and Pseudomonas aeruginosa. This investigation not only shed light on the fish innate immunity that will be essential for the aquaculture industry, but will also provide a foundation for further application of DrIntL-2 in bacteria detection and identification.

O-Antigen Extraction, Purification, and Chemical Conjugation to a Carrier Protein

A variety of bacterial infections have been tackled by glycoconjugates over the recent years, and more vaccines are either under development at preclinical level or in clinical trials. So far, licensed glycoconjugate vaccines have made use of capsular polysaccharides or derived fragments. Today, many glycoconjugates are making use of other classes of sugars, in particular, the O-antigen portion of lipopolysaccharide molecules. Here, we report a simplified method for O-antigen extraction and purification that avoids the step of lipopolysaccharide isolation. Also, a selective chemistry for terminal linkage of O-antigen chains to a carrier protein is described, together with analytical methods for intermediates and final conjugate characterization.