title: Structural and serological studies of the O-antigen of the bacterium Proteus vulgaris OX2 (serogroup O2) used in the Weil-Felix test.
abstract: Based on monosaccharide analysis and 1H- and 13C-NMR spectroscopy, the following structure of the O-specific polysaccharide chain of Proteus vulgaris OX2 lipopolysaccharide (LPS), which defines the O2 specificity of Proteus, was established: [formula: see text] where L-QuiNAc is N-acetyl-L-quinovosamine (2-acetamido-2,6-dideoxy-L-glucose). Various strains of P. vulgaris OX2 used in the Weil-Felix test for serodiagnosis of rickettsiosis (spotted fevers, except for Rocky Mountain spotted fever) were shown to produce LPS with the same O-specific polysaccharide, which differs structurally and serologically from LPS of P. vulgaris OX19 used as antigen for serodiagnosis of typhus and Rocky Mountain spotted fever. O-Acetyl groups present in the polysaccharide are not important for manifesting the immunospecificity. ELISA confirmed that the epitope responsible for the cross-reactivity between sera from patients with Japanese spotted fever and P. vulgaris OX2 cells is located on the P. vulgaris LPS. At the same time, no cross-reaction was observed between rabbit anti-P. vulgaris OX2 antibodies and the spotted fever group (SFG) rickettsial cells. Therefore, human anti-SFG rickettsial antibodies and rabbit anti-P. vulgaris OX2 antibodies may bind to distinct epitopes on P. vulgaris OX2 LPS, and no epitope recognized by rabbit anti-P. vulgaris OX2 antibodies is present on the LPS or any other surface antigen of SFG rickettsiae.
authors.affiliation: Center of Microbiology and Virology, Polish Academy of Sciences, Lodz, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Cedzynski
authors.lastname: Knirel YuA
authors.forename: K I
authors.initials: KI
authors.lastname: Amano
authors.forename: A S
authors.initials: AS
authors.lastname: Swierzko
authors.forename: N A
authors.initials: NA
authors.lastname: Paramonov
authors.forename: S N
authors.initials: SN
authors.lastname: Senchenkova
authors.forename: W
authors.initials: W
authors.lastname: Kaca
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D003429:Cross Reactions; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D019081:O Antigens / Q000737:chemistry* / Q000276:immunology*; D011514:Proteus vulgaris / Q000276:immunology*; D012699:Serology
chemical_list: D019081:O Antigens