Structural and serological studies on a new acidic O‐specific polysaccharide of <i>Proteus vulgaris</i> O32

Abstract

The following structure of the O‐specific polysaccharide chain (O‐antigen) of the Proteus vulgaris O32 lipopolysaccharide (LPS) was established by 1 H‐NMR and 13 C‐NMR spectroscopy, including two‐dimensional NOESY and H‐detected 1 H, 13 C heteronuclear multiple‐quantum coherence (HMQC) experiments : ←2)‐α‐ L ‐Rha p I ‐(1←2)‐α‐ L ‐Rha p II ‐(1←4)‐β‐ D ‐Gal p A I ‐(1←3)‐β‐ D ‐Glc p NAc‐(1←4)‐α‐ D ‐Gal p A II ‐(1←. In addition, an O ‐acetyl group was detected, which, most probably, is located at position 3 of a part of Rha p 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 α‐ 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.