Outer membranes of a lipopolysaccharide-protein complex (LPS-17 kDa protein) as chemical tularemia vaccines.

Immunisation with outer membranes of Francisella tularensis induced an efficient protection in guinea pigs against challenge with the virulent strains 503 or 144/713 (type B biovar holarctica), both clinical isolates, and prevented the development of typical signs of infection in hamadryads (baboons), challenged with the virulent strain Schu (type A, biovar tularensis) of F. tularensis. Immunisation with a lipopolysaccharide protein complex isolated from the outer membranes afforded protection in CBA mice against challenge with strain 503. Another LPS-protein complex obtained by the simple mixture of LPS preparations from strain 503 and a 17-kDa membrane protein from the avirulent R-variant of the vaccine strain 15 also demonstrated protective properties against experimental tularemia in mice.

[The determination of the antigenic determinant of protective monoclonal antibodies specific to the Francisella tularensis lipopolysaccharide]. / Opredelenie antigennoi determinanty preventivnykh monoklonal'nykh antitel, spetsifichnykh k lipopolisakharidu Francisella tularensis.

F. tularensis lipopolysaccharide (LPS) was studied with the use of monoclonal antibodies (McAb) having protective properties. The binding site of these McAb (IgG2a) is localized on the O-chain of LPS. In contrast to LPS isolated from vaccine strain 15, LPS isolated from F. tularensis cells in the R-form has no O-chains and does not interact with McAb.

[Biochemical, antigenic and protective properties of the outer membrane of tularemia pathogens]. / Izuchenie biokhimicheskikh, antigennykh i protektivnykh svoistv vneshnei membrany vozbuditelia tuliaremii.

The outer membranes of Francisella tularensis were studied. The membranes were identified morphologically, immunologically and biochemically. They contained 12-20% of protein, 15-30% of carbohydrates, up to 40% of lipids. The main integral proteins of the outer membranes were the 47, 43, 17 and 12 kD proteins. The main protein 63 kD was not integral. The lipopolysaccharides isolated from the outer membranes and acetone-dried cells did not possess the protective properties in experimental tularemia. The preparations of outer membranes possessed the protective properties for mice infected with the virulent strain 503. Chitosan amplified the protective properties of outer membranes.

[Bacterial antigenic polysaccharides. 12. Structure and 13C NMR spectrum of the polysaccharide chain of Shigella boydii type 8 lipopolysaccharide]. / Antigennye polisakharidy bakterii. 12. Ustanovlenie struktury i interpretatsiia spektra 13C-IaMR spetsificheskoi polisakharidnoi tsepi lipopolisakharida Shigella boydii tip 8.

A specific acidic polysaccharide was isolated from Sh. boydii type 8 antigenic lipopolysaccharide after mild hydrolysis followed by chromatography on Sephadex G-50. The polysaccharide consists of D-glucuronic acid, D-galacturonic acid, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose and 2-amino-1,3-propanediol residues in 1:1:1:1:1 ratio. From the results of methylation analysis, partial acid hydrolysis and Smith degradation, the structure of the repeating unit of the specific polysaccharide was deduced as: (Formula: see text). The 13C NMR spectra of native, O-deacetylated and carboxyl-reduced polysaccharides, as well as the spectrum of oligosaccharide produced by Smith degradation were interpreted. The 13C NMR data fully confirmed the structure of the polysaccharide repeating unit.