[An immunological analysis of bacterial persistence in the bone marrow]. / Immunologicheskii analiz bakterial'noi persistentsii v kostnom mozge.

A method for the evaluation of bacterial persistence in the bone marrow in association with particular clonogenic target cells was developed. The method was based on the negative selection of cells expressing microbial antigens after treatment with hyperimmune antiserum specific to a given infective agent and the subsequent quantitation of target cells thus eliminated in appropriate assays. Using this approach, we demonstrated that Mycoplasma arthritidis and L-forms of Streptococcus strain L-406 were capable of persisting in murine bone marrow in close association with CFUs-7 (a subpopulation of hematopoietic stem cells) for at least several months after experimental infection. Francisella tularensis was also found to be capable to express on the CFUs-7 membranes. Persisting microorganisms enhanced both proliferation and migration of CFUs-7.

[Mutations in Francisella tularensis, decreasing the virulence of these bacteria and leading to a change in the immune response upon infection of experimental animals with them]. / Mutatsii u Francisella tularensis, snizhaiushchie virulentnost' étikh bakterii i privodiashchie k izmeneniiu immunnogo otveta pri zarazhenii imi éksperimental'nykh zhivotnykh.

The research was aimed at isolation of Francisella tularensis mutants possessing the decreased virulence for experimental animals and mediating the changes in the animal immune response. A number of spontaneous and induced mutants of the American and European subtypes of Francisella tularensis were selected for antibiotics resistance or detergent sensitivity. All the obtained mutants have the decreased virulence and differ in their ability to induce the protective antitularemia immunity or ability to induce the humoral immune response in the laboratory animals. The dimeric immunoprecipitation in gel as well as immunoblotting have shown the mutations decreasing the virulence to cause the loss by bacteria of a number of antigenic structures (in case the virulence is completely lost) or changes in antigenic structure resulting in inability of bacteria to induce the humoral immune response when immunizing the laboratory animals. The latter occurs in partially virulent mutants of the vaccine mutant type. The concomitant changes in virulence, ability to cause protective immunity or humoral immune response of the mutants is discussed.

[Detection of tularemia pathogens in patients with the use of an immunofluorescence reaction]. / Obnaruzhenie vozbuditelia tuliaremii u bol'nykh s pomoshch'iu reaktsii immunofliuorestsentsii.

For the first time three cases of the detection of Francisella tularensis, made by means of the direct immunofluorescence test in the fluid obtained from punctured buboes or in purulent matter taken from patients with the ulcerous bubonic form of tularemia, are presented. The simplicity of the test and its capacity of yielding rapid results make it possible to recommend this test, together with other diagnostic methods, for the clinical diagnosis of tularemia.

[Delayed type hypersensitivity reaction in the pathogenesis and formation of immunity in tularemia infections in mice]. / Reaktsiia giperchuvstvitel'nosti zamedlennogo tipa v patogeneze i formirovanii immuniteta pri tuliaremiinoi infektsii u myshei.

As a result of our studies, strain differences in the sensitivity of CBA and BALB/c mice to partially attenuated Francisella tularensis strain have been revealed. Relationship between the increased migration of lymphocytes to the liver and lymphoid organs and the intensive development of cell-mediated immunity reactions has been shown. An important role of local reactions (the skin at the site of the inoculation of F. tularessis + a regional lymph node) in the development of the pathological process and the formation of immunity to tularemia infection has been noted. A high level of resistance to F. tularensis strain used for inoculation in BALB/c mice seems to be greatly due to the fact that in these mice more intensive cell-mediated immunity reactions develop at the early stages of infection, than in CBA mice.

[Time periods of antibody preservation in patients convalescing from hemorrhagic fever with renal syndrome in European foci of the infection]. / O srokakh sokhraneniia antitel u rekonvalestsentov gemorragicheskoi likhoradki s pochechnym sindromom v evropeiskikh ochagakh infektsii.

The radioimmunoassay of serum samples from 76 convalescents after hemorrhagic fever with the renal syndrome (HFRS), that took place in 1964 in Ufa, revealed the presence of specific antibodies in 75% of the convalescents. The absence of antibodies may be attributed both to their loss in some of the convalescents and to mistakes in the clinical diagnosis. The study of serum samples from 19 convalescents who had the infection in 1960 during the laboratory outbreak of HFRS at the Gamaleya Institute of Epidemiology and Microbiology (Moscow) showed the presence of antibodies in all convalescents. In both groups the infection was linked with common red-backed voles (the Western serological variant of the virus).

[The effect of aerosolization on the changes in major biological properties of the vaccine strain of Francisella tularensis]. / Vliianie aérozolirovaniia na izmenenie osnovnykh biologicheskikh svoistv vaktsinnogo shtamma Francisella tularensis.

The exposure of F. tularensis vaccine strain 15/10 in the form of aerosol for more than 10 minutes results in the decrease of its virulence, immunogenicity and the content of species-specific antigen and in the increase of the dissociation level. Proceeding from this fact, during aerosol immunization with this vaccine strain exposure must not exceed 5 minutes for unstabilized aerosol and 10 minutes for aerosol stabilized with 5% glycerin. Under these conditions the properties of F. tularensis strain 15/10 are retained practically on the initial level.

[Cytopathic effect of the tularemia microbe on a culture of peritoneal macrophages]. / Izuchenie tsitopaticheskogo deistviia tularemiinogo mikroba na kul'turu peritoneal'nykh makrofagov.

Morphological analysis of the process of interaction of tularemia microbe strains differing by virulence with macrophages demonstrated that all these strains produced a lethal effect on macrophages obtained from the animales sensitive to the infection. The macrophages obtained from the animals were but little sensitive to tularemia and were resistant to the action of the causative agent of this infection. The data obtained led to a supposition on the presence in the tularemia causative agent of a factor responsible for its lethal action on the macrophages.

[Detection of the causative agent of tularemia in the organs of animals in the early stages of development of the infection]. / Obnaruzhenie vozbuditelia tuliaremii v organakh zhivotnykh na rannikh étapakh razvitiia infektsii

A study was made of a possibility of detection of the causative agent of tularemia in the organism of albino mice at early stages of development of the infection after subcutaneous infection with 1, 10 and 100 microbial cells of strains No. 503/834 (Holarctic race) and Schu (nearctic race). The following examinations were made: cultivation on nutrient media, immunofluorescent study, the antibody neutralization test and the passive hemagglutination test with erythrocytic diagnostic agents. The microbe could be regularly revealed three days after the infection. Detection of the causative agent was possible in individual cases at the earlier dates by seeding and by the fluorescent antibody method. Although by cultivation it is possible to reveal individual microbes, but the growth appears on the 3rd--5th day and later. The most rapid response (1.5--2 hours) results (on the presence of the microbe) can be obtained with the aid of the fluorescent antibody method. Application of the mentioned tests with the erythrocytic diagnostic agents permits to obtain data not only on the presence of the causative agent, but also on its quantity of the causative agent in the organism of the infected animal. The mentioned methods provide the most complete characteristics of the dynamics of the accumulation of the microbe in the animal organism.