Taxonomic group: bacteria / Firmicutes
(Phylum: Firmicutes)
Associated disease: infection due to Streptococcus pneumoniae [ICD11:
XN3PW 
]
NCBI PubMed ID: 12496169Journal NLM ID: 0246127Publisher: American Society for Microbiology
Correspondence: jyother
uab.edu
Institutions: Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35294
The Streptococcus pneumoniae capsular polysaccharides and pneumococcal surface protein A (PspA) are major determinants of virulence that are antigenically variable and capable of eliciting protective immune responses. By genetically switching the pspA genes of the capsule type 2 strain D39 and the capsule type 3 strain WU2, we showed that the different abilities of antibody to PspA to protect against these strains was not related to the PspA type expressed. Similarly, the level of specific antibody binding to PspA, other surface antigens, and surface-localized C3b did not depend on the PspA type but instead was correlated with the capsule type. The type 3 strain WU2 and an isogenic derivative of D39 that expresses the type 3 capsule bound nearly identical amounts of antibody to PspA and other surface antigens, and these amounts were less than one-half the amount observed with the type 2 parent strain D39. Expression of the type 3 capsule in D39 also reduced the amount of C3b deposited and its accessibility to antibody, resulting in a level intermediate between the levels observed with WU2 and D39. Despite these effects, the capsule type was not the determining factor in anti-PspA-mediated protection, as both D39 and its derivative expressing the type 3 capsule were more resistant to protection than WU2. The specific combination of PspA and capsule type also did not determine the level of protection. The capsule structure is thus a major determinant in accessibility of surface antigens to antibody, but certain strains appear to express other factors that can influence antibody-mediated protection.
virulence, Streptococcus pneumoniae, capsular polysaccharide, pneumococcal, immune response, surface antigens
Structure type: polymer chemical repeating unit
Location inside paper: p.219
Trivial name: capsule type 2
Compound class: CPS, polysaccharide, rhamnoglucan
Contained glycoepitopes: IEDB_115136,IEDB_136105,IEDB_140630,IEDB_142488,IEDB_144998,IEDB_146664,IEDB_225177,IEDB_885823,IEDB_983931,SB_192
Methods: ELISA, Western blotting, Southern blotting, transcription analysis, antibody binding, complement assays, generation of polyclonal antiserum, protection studies
Biological activity: immunological data
Biosynthesis and genetic data: genetic data
Related record ID(s): 289, 6395, 10368, 10522, 23803
NCBI Taxonomy refs (TaxIDs): 373153Reference(s) to other database(s): GTC:G67978MJ, GlycomeDB:
25030
Show glycosyltransferases
There is only one chemically distinct structure:
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