Structural and serological studies of the O-antigen of the bacterium Proteus vulgaris OX2 (serogroup O2) used in the Weil-Felix test.
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.
Cedzynski
M
M
Center of Microbiology and Virology, Polish Academy of Sciences, Lodz, Poland.
Knirel YuA
Amano
K I
KI
Swierzko
A S
AS
Paramonov
N A
NA
Senchenkova
S N
SN
Kaca
W
W
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
D019081:O Antigens