Detailed Investigation of the Immunodominant Role of O-Antigen Stoichiometric O-Acetylation as Revealed by Chemical Synthesis, Immunochemistry, Solution Conformation and STD-NMR Spectroscopy for Shigella flexneriâ
3a.
Chemistry
; 22(31): 10892-911, 2016 Jul 25.
Article
in En
| MEDLINE
| ID: mdl-27376496
ABSTRACT
Shigella flexneriâ
3a causes bacillary dysentery. Its O-antigen has the {2)-[α-d-Glcp-(1â3)]-α-l-Rhap-(1â2)-α-l-Rhap-(1â3)-[Acâ2]-α-l-Rhap-(1â3)-[Acâ6]≈40 % -ß-d-GlcpNAc-(1â} ([(E)ABAc CAc D]) repeating unit, and the non-O-acetylated equivalent defines S. flexneriâ
X. Propyl hepta-, octa-, and decasaccharides sharing the (E')A'BAc CD(E)A sequence, and their non-O-acetylated analogues were synthesized from a fully protected BAc CD(E)A allyl glycoside. The stepwise introduction of orthogonally protected mono- and disaccharide imidate donors was followed by a two-step deprotection process. Monoclonal antibody binding to twenty-six S. flexneri typesâ
3a and X di- to decasaccharides was studied by an inhibition enzyme-linked immunosorbent assay (ELISA) and STD-NMR spectroscopy. Epitope mapping revealed that the 2C -acetate dominated the recognition by monoclonal IgG and IgM antibodies and that the BAc CD segment was essential for binding. The glucosyl side chain contributed to a lesser extent, albeit increasingly with the chain length. Moreover, tr-NOESY analysis also showed interaction but did not reveal any meaningful conformational change upon antibody binding.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Shigella flexneri
/
Magnetic Resonance Spectroscopy
/
O Antigens
Limits:
Animals
Language:
En
Journal:
Chemistry
Journal subject:
QUIMICA
Year:
2016
Document type:
Article
Affiliation country:
France