Polysaccharide Antigens ofPseudomonas Aeruginosa

Abstract

The major polysaccharide antigens of P. aeruginosa are the cell-wall lipopolysaccharides many of which have an acidic polysaccharide chain (O-antigen) rich in unusual amino sugars. The D-rhamnose-rich polysaccharide antigen common to many serologically distinct strains is also associated with the lipopolysaccharide. The high-molecular-weight polysaccharides with O-specificity are present in extracellular slime produced by strains isolated from the environmental and from the immunocompromised hosts. The extracellular antigenic polysaccharide of another type (bacterial alginate) is expressed by mucoid strains isolated from patients with cystic fibrosis. Serotype-specific immune responses after infection are directed at the lipopolysaccharides and these heat-stable antigens serve as the basis for differentiation of P. aeruginosa strains. Both the cell-wall antigens including conjugates of the O-polysaccharides with different proteins and the extracellular antigens have been used to prepare specific antibodies tested for protection against infections due to P. aeruginosa.

Functional analysis of genes responsible for the synthesis of the B-band O antigen of Pseudomonas aeruginosa serotype O6 lipopolysaccharide The GenBank accession number for the sequence reported in this paper is AF035937.

“…Finally, a fourth transferase, WbpR, likely adds the fourth residue, -Rha, to the B-band unit. -Rha is found both in the O antigen and in the core oligosaccharide of serotype O6 (Knirel, 1990 ;Masoud et al, 1995). In bacteria, -Rha synthesis is encoded by the highly conserved rmlABCD genes (Macpherson et al, 1994 ;Reeves, 1993).…”

“…Therefore, the enzymes for -Rha synthesis are not encoded by genes within the O antigen cluster but may well be encoded by the rml cluster. The structure of the repeating unit of the serotype O6 O antigen has been chemically elucidated (Knirel, 1990 ;Knirel & Kochetkov, 1994). However, the identity of the first sugar residue attached to the core has not been determined.…”

“…The serotype-specific antigen is B-band LPS, the O antigen of which is a heteropolymer composed of di-to-pentasaccharide repeats (Knirel & Kochetkov, 1994). Structural studies (Knirel, 1990 ;Knirel & Kochetkov, 1994) indicated that the O antigen of IATS serotype O6 is a repeating linear tetrasaccharide with the structure shown in Fig. 1.…”

Synthesis, Characterization, and Immunological Properties of LPS-Based Vaccines Composed of O-Polysaccharides Conjugated with Recombinant Exoprotein A from <i>Pseudomonas aeruginosa</i>

“…The serum antibodies against the surface O-PS antigen confer protective immunity against the pathogen. Since intact LPS of Gram-negative bacteria is highly toxic, and isolated O-PS molecules are poor immunogens, especially in infants, thus many investigators have attempted to conjugate O-PS of pathogenic bacteria to immunogenic proteins to enhance the immunogenicity of O-PS and confer protection against the pathogen [11] [12].…”

Crystal Structure of WbpP, a Genuine UDP-N-acetylglucosamine 4-Epimerase from Pseudomonas aeruginosa

“…Variation in the structural composition of O antigen has been linked to various aspects of bacterium-host interactions, including virulence potential (4). In the clinically relevant human pathogen Pseudomonas aeruginosa serotype O6, the O antigen is composed of a tetrasaccharide repeating unit of 3␣-D-3-O-acetyl,6-amino-GalNAc-(134)-␣-D-6-amino-2-deoxy-2-formamido-D-galacturonic acid-(133)-␣-D-2-acetamido-2,6-dideoxy-D-glucose-(132)-␣-L-Rha-(13 (5). Biosynthesis of this repeating unit is catalyzed by enzymes encoded in the wbp gene cluster (6).…”