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The protective properties of the preparation of F. tularensis outer membranes (OM), obtained from F. tularensis vaccine strain 15, were studied in experiments on hamadryas baboons challenged subcutaneously with F. tularensis virulent strain Schu (nonarctic subspecies). The subcutaneous immunization with the OM preparation prevented the development of clinically pronounced infection in more than 70% of the monkeys challenged with F. tularensis strain Schu in a dose of 787 live microbial cells 30 days after immunization. Antibody titers determined in the immunized monkeys with the use of the agglutination test (AT) and the passive hemagglutination test (PHAT) were usual in minimal diagnostic limits (1:80 for AT and 1:320 for PHAT) and did not significantly rise by day 20 after immunization. In all intact animals infected with F. tularensis strain Schu the development of the infectious process was registered, which was accompanied by a rise in temperature exceeding 39.5 degrees C and a rise in the titer of specific antibodies.

Subcutaneous immunization, made in a single injection, with outer membrane preparations obtained from F.tularensis vaccine strain 15 and virulent strain A'Cole results in intensive immunity to tularemia in guinea pigs, ensuring the protection of 60-100% of the animals within a month after challenge with F.tularensis virulent strain 503 in a dose of 1,000 DCL. The development of protective effect induced by F.tularensis outer membranes can be observed during the first 24 hours and reaches its maximum by days 15-21 after immunization.

A method for early diagnosis of cholelithiasis on a basis of the hemagglutination inhibition reaction has been suggested. A method is realized in interaction of a specific agglutinogen obtained from lithogenic bile with the human blood serum and erythrocytes of white mongrel rats. It was established that agglutinogen is a protein with a low molecular mass of 55,000-75,000. A specificity of the method is 74-100%. The method is simple in technical performance, needs no special equipment and training of personnel. High productivity (150-200 analyses can be performed by one investigator per one shift) as compared to ultrasound investigation makes it capable to compete in mass screenings.

LPS-protein complex containing proteins of 15 kD, 17 kD and 19 kD was isolated from F. tularensis outer membrane by solving with sodium deoxycholate with the subsequent gel filtration on Sephacryl S-200. Protein of 17 kD constituted the main protein component of the complex. The LPS-protein ratio of this complex was 1:1. Proteins contained in LPS-protein complex have mainly the alpha-spiral structure. In the absence of detergent these proteins and LPS formed micelles with molecular weight exceeding 10(7) D. LPS-protein complex was shown to have a protective effect in mice infected with F. tularensis virulent strain 503.

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.