Synthesis and immunochemical characterization of neoglycoproteins containing epitopes of the inner core region of Pseudomonas aeruginosa RNA group I lipopolysaccharide

The disaccharide allyl 2-acetamido-2-deoxy-alpha -D-galactopyranosyl-(1 -->3)-7-O-carbamoyl-L-glycero-alpha -D-manno-heptopyranoside 5 (GalNAc-cmHep-allyl) was synthesized starting from 1 and 2. Compound 5, cmHep-allyl and the disaccharide cmHep-(1 -->3)-Hep-allyl were converted into cysteamine-spacered derivatives and conjugated to bovine serum albumin (BSA) to yield the neoglycoconjugates 7-9, respectively, These conjugates were used to immunize mice and to prepare monoclonal antibodies (mAbs) which were characterized in comparison to mAbs obtained after immunization with heat-killed Pseudomonas aeroginosa strain H4, Two antibodies obtained after immunization with the neoglycoconjugates bound strongly to cmHep-BSA and with lower affinity to cmHep-Hep-BSA but did not bind to GalNAc-cmHep-BSA or to H4 LPS. Another antibody obtained after immunization with heat-killed bacteria bound to LPS and GalNAc-cmHep-BSA but not to cmHep-Hep-BSA or cmHep-BSA.