Karin Leontein

Structural studies of the O-antigenic polysaccharide of Escherichia coli O86, which possesses blood-group B activity

The O-specific side-chains of the lipopolysaccharide from Escherichia coli O86:K2:H2 have been investigated using n.m.r. spectroscopy, methylation analysis, and specific degradations, and shown to be composed of the pentasaccharide repeating-unit (formula; see text) which represents the biological repeating-unit. The blood-group B activity was confirmed by an enzyme-linked immunosorbent assay.

Structural studies of the O-antigen polysaccharide of Salmonella thompson, serogroup C1 (6,7)

The structure of the O-antigen polysaccharide of Salmonella thompson, serogroup C1 (6,7) has been investigated mainly by methylation analysis, n.m.r. spectroscopy, specific degradations by a phage-associated enzyme, N-deacetylation-deamination, and f.a.b.-m.s. It is concluded that the structure involves the following repeating unit. (formula; see text) There are two populations of chains, with and without alpha-D-glucopyranosyl groups, 3-linked to an alpha-D-Manp residue, and only the latter type is hydrolysed by the phage enzyme. The alpha linkage of the third Manp residue is cleaved by the O14 phage enzyme. The structure, with or without the alpha-D-glucopyranosyl group, represents the biological repeating-unit.

Synthesis of the methyl and 1-octyl glycosides of the P-antigen tetrasaccharide (globotetraose)

The methyl and 1-octyl beta-glycosides of the P-antigen tetrasaccharide [globotetraose, beta-D-GalpNAc-(1----3)-alpha-D-Galp-(1----4)-beta-D-Galp-(1----4) -D-Glc] were synthesised from a tetrasaccharide precursor, prepared using methyl disaccharide 1-thioglycosides as intermediates. In the key glycosidation with silver triflate, HO-2 was used as an alpha-directing group in the glycosyl bromide.

Structural studies of Escherichia coli O127 O-antigen polysaccharide

The O-specific side-chain of the lipopolysaccharide from Escherichia coli O127a:H- (O127a:4932-53) has been investigated using 2D NMR spectroscopy, methylation analysis, and partial solvolysis with anhydrous hydrogen fluoride as the principal methods. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the following structure. -->2)-alpha-L-Fucp-(1-->2)-beta-D-Galp-(1-->3)-alpha-D-GalpNAc-(1- ->3)-alpha-D- GalpNAc-(1--> The polysaccharide contains approximately one mole of O-acetyl groups per repeating unit distributed over several positions.

Structural studies of the Escherichia coli O78 O-antigen polysaccharide

The structure of the O-antigen polysaccharide from Escherichia coli O78 has been investigated; methylation analysis, partial solvolysis with liquid hydrogen fluoride, and 2D-n.m.r. spectroscopy were the principal methods used. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the following structure.----3)-beta-D-GlcpNAc-(1----4)-beta-D-GlcpNAc- (1----4)-beta-D-Manp-(1----4)-alpha-D-Manp-(1----

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 12A

The structure of the capsular polysaccharide elaborated by Streptococcus pneumoniae type 18F (S18F) has been investigated by using n.m.r. spectroscopy, methylation analysis, and characterisation of oligosaccharides obtained on partial hydrolysis. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure. (formula; see text) In this structure, the absolute configuration of the glycerol phosphate moiety has not been determined, but is assumed to be D-glycerol 1-phosphate (sn-glycerol 3-phosphate). The location of an O-acetyl group at O-6 of the terminal alpha-D-glucopyranosyl groups is tentative only.

Bordetella pertussis lipopolysaccharide as antigen in ELISA for serological diagnosis of whooping cough

Abstract Bordetella pertussis lipopolysaccharide (LPS) was investigated as antigen for serological diagnosis of whooping cough by ELISA in paired samples from 90 patients with culture-confirmed pertussis. Significant IgG titre rises were seen in 70 (78%) of patients, IgM titre rises in 49 (54%) and IgA in 56 (62%). A rise in either IgG or IgM was noted in 74 (82%). In unimmunised children, IgG titre rises were seen in 63 74 (85%), while the corresponding response was noted in only 7 16 (44%) of the previously DTP-immunised children and adults. Inclusion of IgG responses to filamentous haemagglutinin (FHA) increased the diagnostic sensitivity to 96% ( 86 90 positives by titre rises). In the unimmunised group, 73 74 (99%) showed IgG titre rises to either of the antigens. Titre rises to high levels of IgM to the LPS antigen were significantly more common than to FHA or pertussis toxin (PT). In conclusion, the study showed that B. pertussis LPS can be useful as antigen in the serological diagnosis of whooping cough, especially in non-DTP immunised populations.