STRUCTURES OF THE O-ANTIGENS OF PROTEUS-BACILLI BELONGING TO OX GROUP(SEROGROUPS O1-O3) USED IN WEIL-FELIX TEST

Structures of the O-specific polysaccharide chains of lipopolysacchari des from Proteus group OX strains (serogroups O1-O3) used as antigens in Weil-Felix test for diagnosis of rickettsiosis, were established. F rom them, the acid-labile polysaccharide of Proteus vulgar is OX19 (O1 ) is built up of the following branched pentasaccharide repeating unit s connected via a phosphate group: [GRAPHICS] where QuiNAc stands for 2-acetamido-2,6-dideoxyglucose (N-acetylquinovosamine). The basis of s erospecificity of the Proteus group OX antigens and their cross-reacti vity with human anti-rickettsial antibodies is discussed. (C) 1997 Fed eration of European Biochemical Societies.