Structural and serological studies on a new acidic O-specific polysaccharide of Proteus vulgaris O32

The following structure of the O-specific polysaccharide chain (O-antigen) of the Proteus vulgaris O32 lipopolysaccharide (LPS) was established by H-1-NMR and C-13-NMR spectroscopy, including two-dimensional NOESY and H-detected H-1,C-13 heteronuclear multiple-quantum coherence (HMQC) experiments: -->2)-alpha-L-Rhap(I)-(1-->2)-alpha-L-Rhap(II)-(1-4)-beta-D-GalpA'-(1 -->3)-beta-D-GlcpNAc-(1-->4)-alpha-D-GalpA(II)-(1-->. In addition, an O-acetyl group was detected, which. most probably, is located at position 3 of a part of Rhap(I) residues. Serological studies, using rabbit polyclonal anti-(P. vulgaris O32) serum, homologous and heterologous Proteus O-antigens and related artificial antigens, revealed the importance of an alpha-D-GalA-associated epitope in manifesting the immunospecificity of P. vulgaris O32 and substantiated serological relationships between the O-antigen studied and those of some other Proteus strains.