Structural and Immunochemical Aspects of Brucella Abortus Endotoxins

Abstract

The smooth lipopolysaccharide (sLPS)-protein complex of Brucella abortus has been identified as the immuno-dominant component, which reacts with antibody in the serological tests generally used for diagnosis of brucellosis (1). B. abortus sLPS carries the major A (abortus) antigen, the species-specific epitope located within, and the minor M (melitensis) determinant, which cross reacts with B. melitensis antigen. O-chain prepared fromB. abortus LPS was reported to have protective antigen properties in mice (2). Unlike the LPS of other enterobacteriaceae, sLPS separates primarily into the phenol phase when B. abortus cells are extracted with hot phenol-water by the Westphal method (3–7). The crude fraction of sLPS, which was used to study the properties of smooth B. abortus in the early eighties, is associated with various proteins ranging from 10–30% of the weight composition, most of which are non-covalently bound (3). These non-covalently linked proteins or nucleic acids can be removed by treatment with chaotropic agents and by gel filtration in the presence of chaotropic agents and detergents.

Most of the material in this article is from references 9 and 10. We thank Martinus Nijhoff/Dr. W. Junk Publishers for giving such permission. We use O-chain instead of O-hapten to express the O-antigen moiety of LPS. The terminology of O-antigen is not suitable in this case because it reacts as a hapten rather than as an antigen. See references 7, 9, and 10.