Anti-S. pneumoniae CWPS monoclonal antibody

The cell wall of Gram-positive bacteria contains a layer of carbohydrate-rich peptidoglycan, and the thick peptidoglycan layer is a reticulated structure consisting of alternating β-1,4-linked N-acetylmuramic acid and N-acetylglucosamine chains covalently linked by pentapeptides. In addition to its primary functions in morphology and protection, it acts as a scaffold for proteins such as cell wall polysaccharides (CWPS) and other glycopolymers of Gram-positive bacteria. CWPS in streptococci include lipoteichoic acid (LTA), rhamnose-glucose polysaccharide (RGP), and exopolysaccharides (EPS), of which RGP and EPS are likely to be part of the capsular polysaccharides produced by many streptococci, inhibit complement activity and phagocytosis, and are therefore an important virulence factor for pathogenic streptococci. RGP in pathogenic streptococci is closely related to strain virulence, drug resistance, and immune evasion, whereas it is absent in Streptococcus pneumoniae, which contains wall teichoic acids (WTAs) and LTAs, and the cell surface is covered with capsule, whose structure varies considerably from strain to strain. CWPS of pathogenic streptococci have received much attention due to their pathogenicity and role in biofilm formation, and peptidoglycan-anchored LTAs have been identified as virulence factors for Streptococcus pneumoniae.

Figure 1. Schematic representation of the major cell-wall polysaccharides in the cell wall of important streptococcal species
(Source: Kampff Z, et al. 2023)

In contrast to other streptococci, the cell wall of Streptococcus pneumoniae has a very complex structure. It has the same WTA and LTA repeat units, with different strains defined by peptidoglycan or membranes in anchoring positions. Bioinformatics analysis of different Streptococcus pneumoniae strains by the researchers proposed a pathway for the synthesis of teichoic acid (TA). The genes involved in TA biosynthesis are located at three genomic loci (lic1, lic2, and lic3), and the lic1 operon contains genes involved in choline uptake, CDP-choline, and CDP-ribitol synthesis. The adjacent lic2 region encodes a phosphotransferase and putative TA flippase. lic3 region differs from the lic1 and lic2 gene clusters in its location on the chromosome, and the functions of its gene product include phosphotransferase, glycosyltransferase, and integral membrane protein. TA flippase specifically binds to choline-containing TA precursor chains on untransferred cytoplasmic membranes, thus demonstrating that all mature TAs are decorated with choline residues, which is essential for choline-dependent growth of S. pneumoniae. Subsequently, the mature TA chains were anchored to peptidoglycan or the cell membrane to form WTA or LTA, respectively.

Figure 2. Genetic organisation of the lic regions of Streptococcus pneumoniae R6 and associated functions of the gene products
(Source: Kampff Z, et al. 2023)

Anti-Streptococcus pneumoniae CWPS monoclonal antibody
Anti-Streptococcus pneumoniae cell wall polysaccharides monoclonal antibody
Anti-S. pneumoniae cell wall polysaccharides monoclonal antibody