[The need for a review of the procedure for the preventive vaccination of researchers working with Rickettsia prowazekii]. / Neobkhodimost' peresmotra taktiki profilakticheskoi vaktsinatsii sotrudnikov, rabotaiushchikh s Rickettsia prowazekii.

The analysis of the results of prolonged observations on the prophylactic immunization of employees working with R. prowazekii is presented. The necessity of the differentiated approach to the determination of the immunization schedule and the choice of vaccine is shown. The presence of specific antibodies (Ab) and the level of their titers have been found to be related to the degree of anti-infectious protection. The following characteristics indicate the presence of profound immunological transformation in vaccinees: complement-fixing Ab in titers 1:10 and more and/or immunofluorescent Ab in titers not below 1:180, Ab to protein in the hemagglutination test in titers not below 1:1000. These specific Ab and the level of their titers can be registered after the second injection of live combined typhus vaccine E and the third injection of chemical typhus vaccine. Cases of laboratory infection and their relationship to the character of immunization and the intensity of contacts with R. prowazekii virulent strains are discussed. Attention is drawn to the strict observance of professional safety rules.

[The protective activity of individual proteins and immunogenic fractions isolated from Rickettsia prowazekii]. / Issledovanie protektivnoi aktivnosti individual'nykh belkov i immunogennykh fraktsii, vydelennykh iz Rickettsia prowazekii.

The immunogenic properties and protective activity of basic protein I and tris-soluble antigens isolated from R. prowazekii were analyzed in comparison with those of chemical typhus vaccine on the model of anti-infectious immunity in guinea pigs. The analysis revealed that purified protein I has protective activity for guinea pigs, which is less pronounced in protein I from strain E with weak pathogenicity than protein I from strains EVir and Breinl. The activity and immunogenic properties of tris-soluble antigens, especially antigen I, are comparable with those of chemical typhus vaccines in the parameters under study.

Protein antigens of genetically related Rickettsia prowazekii strains with different virulence.

The protein antigens of two distinct lines of genetically related strains, namely the nonpathogenic strain E and its virulent revertant EVir and of the standard virulent strain Breinl were compared in SDS-PAGE and immunoblot assay using typhus patient sera and immune rabbit sera. No differences in the polypeptide pattern as detected in SDS-PAGE were found between strain E and EVir; the Breinl strain differed in a 30 kD protein. The high immunogenicity of the protein antigens of E, EVir and Breinl strains was demonstrated by immunoblot assay with human sera, which did not show any differences between the strains studied. Immunoblot analysis with immune rabbit sera to the strain E, EVir, and Breinl showed differences in immunological response to the 70 kD and 60 kD polypeptides of low virulent strain E and those of virulent strains EVir and Breinl.

[Isolation and primary characteristics of the common species-specific outer membrane protein of Rickettsia prowazekii]. / Vydelenie i pervichnaia kharakteristika obshchevidovogo belka naruzhnoi membrany Rickettsia prowazekii.

Common species-specific protein is isolated for the first time in the chromatographically pure state from the outer membrane of Rickettsia prowazekii, and its amino acid composition is determined. As revealed by chromatofocusing technique, the protein possesses pI 4.18 +/- 0.03. Three basic ninhydrin-positive compounds, differing from usual amino acids, were discovered in the protein hydrolyzate. Data suggesting the subunit structure of the isolated protein are presented.

[Electrophoretic and immunochemical characteristics of proteins of Rickettsia prowazekii strains of various virulence]. / Elektroforeticheskaia i immunokhimicheskaia kharakteristika belkov shtamma Rickettsia prowazekii razlichnoi virulentnosti.

PAAG-electrophoresis of the isogenic pair of Rickettsia prowazekii strains E and Evir lysates demonstrate the similarity in polypeptide tracks. The different electrophoretic mobility of the Mr 30 Kd protein from these strains as compared with the mobility of analogous protein from the standard virulent Breinl strain is registered. In immunoblot experiments the specific rabbit antiserums obtained on the 30th day of infection with the Breinl, E or Evir strains demonstrate the presence of the different main antigens 60 Kd or 70 Kd. The difference evidently reflects the specificity of development of two forms of infection by the strains having different virulence. The surface tris-soluble antigens of Rickettsia prowazekii have the similar polypeptide contents and immunochemical properties. The main component of tris-soluble antigens Mr 130 Kd protein is not strain specific having the common thermolabile epitope.