STRUCTURAL-PROPERTIES OF LIPOPOLYSACCHARIDES FROM RICKETTSIA-TYPHI AND RICKETTSIA-PROWAZEKII AND THEIR CHEMICAL SIMILARITY TO THE LIPOPOLYSACCHARIDE FROM PROTEUS-VULGARIS OX19 USED IN THE WEIL-FELIX TEST

The lipopolysaccharides (LPSs) isolated from typhus group (TG) rickett siae Rickettsia typhi and Rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electr ophoresis (SDS-PAGE) followed by silver staining. LPSs from two specie s of TG rickettsiae contained glucose, 3-deoxy-D-manno-octulosonic aci d, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydrox ylmyristic acid and heneicosanoic acid) but not heptose. The O-polysac charides of these LPSs were composed of glucose, glucosamine, quinovos amine, and phosphorylated hexosamine. Resolution of these LPSs by thei r apparent molecular masses by SDS-PAGE showed that they have a common ladder-like pattern. Based on the results of chemical composition and SDS-PAGE pattern, we suggest that these LPSs act as group-specific an tigens. Furthermore, glucosamine, quinovosamine, and phosphorylated he xosamine were also found in the O-polysaccharide of the LPS from Prote us vulgaris OX19 used in the Weil-Felix test, suggesting that they may represent the antigens common to LPSs from TG rickettsiae and P. vulg aris OX19.