Structural and functional characterization of the glycan antigens involved in immunobiology of Q fever.

Coxiella burnetii is the causative agent of Q fever. The bacterium is extremely infectious and is classified as a category biological weapon. A lipopolysaccharide I (LPS I) belongs to the main components of the C. burnetii outer membrane and its structure-function relationship studies are of potential interest. Size-exclusion chromatography revealed noticeable differences in distribution and chemical composition of the O-polysaccharide chains in LPS I. It is likely that C. burnetii is capable of synthesizing chemically distinct subclasses of O-specific polysaccharide molecules differing in their antigenic reactivities. Methylation-linkage analysis indicated the presence of terminal virenose (Vir), dihydrohydroxystreptose (Strep), and mannose (Man), 4-substituted Vir, and 4-substituted Man in the O-specific chain. Serological data indicate that Vir and Strep might be involved in the immunobiology of Q fever.