[The need for a review of the procedure for the preventive vaccination of researchers working with 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.

[Combined (associated) immunization against typhoid, typhus and plague].

The article substantiates epidemiological expediency of complex (associated) immunization of servicemen and population against typhoid, typhus and plague in polyetiological zones of these infections, and also in cases of simultaneous proliferation of these diseases. For simultaneous preventive vaccination against these infections a complex immunization scheme was experimentally substantiated and clinically approved. It is based on national commercial vaccines and ensures a simultaneous administration of 2-3 vaccine preparations by hypodermic syringe or jet injection.

Persistence of Rickettsia prowazekii in cotton rat macrophage cultures.

Rickettsia prowazekii is able to multiply and persist for a long time in cotton rat macrophage culture (29-days observation period). Electron microscopic studies showed that the structure of Rickettsiae remained intact at different intervals post-inoculation (p.i.

Electron microscopic analysis of in vitro interaction of Rickettsia prowazekii with guinea pig macrophages. II. Macrophages from immune animals.

Alike to macrophages from intact animals, reproduction, destruction and formation of spheroplast-like forms were observed in macrophages from immune guinea pigs 2 months post-infection (p.i.) with the virulent Breinl strain of Rickettsia prowazekii.

Electron microscopic analysis of in vitro interaction of Rickettsia prowazekii with guinea pig macrophages. I. Macrophages from nonimmune animals.

Monolayer cultures of peritoneal macrophages of intact guinea pigs were infected with Rickettsia prowazekii (strain Breinl) and examined by electron microscopy after 30 min, 4 and 24 hr post-infection (p.i.).

[Immunogenicity of a chemical typhus vaccine and of a corpuscular radioantigen obtained from Rickettsia prowazekii].

The protective activity of chemical typhus vaccine and R. prowazekii corpuscular radioantigen (CRA) was studied. Guinea pigs were immunized with doses of 32 and 48 antigenic units.

[Doxycycline in experimental rickettsial infection].

The effect of doxycycline on R. prowazekii and R. sibirica was studied in comparison with that of tetracycline on two infection models, i.

[Electron microscopic characteristics of the action of penicillin and vancomycin on Rickettsia conorii and Rickettsia akari in vitro].

The possibility of L-transformation for two species of Rickettsia of the tick group (R. conorii and R. akari) was studied with light and electron microscopy.

[Antigen isolation from Rickettsia prowazekii cultured in FL cells and its use in the macrophage migration inhibition reaction].

An antigen obtained from R. prowazekii cultivated in hydrocortisone-treated FL-cells possesses activity determined in the complement fixation test and the macrophage migration inhibition test. Such antigen can be used in the macrophage migration inhibition test with macrophages obtained from animals immunized with the preparations of rickettsial egg cultures.

Multiplication of Rickettsia prowazekii in cotton rat macrophage cultures.

The susceptibility of cotton rat macrophages to Rickettsia (R.) prowazekii, the percentage of the affected cells, and the intensity of damage to individual cells by rickettsiae were found to be much higher than those in guinea pig macrophages infected under similar conditions. At the same time, cotton rat macrophages proved to be more resistant to the effect of rickettsiae than guinea pig macrophages.

[Combined action of penicillin, tetracycline and rifampicin on R. sibirica and R. prowazekii in experiments on chick embryos].

The effect of combinations of penicillin, tetracycline and rifampicin on R. prowazekii (the causative agent of typhus) and R. sibirica (the causative agent of tick-borne rickettsiosis of the North Asia) was studied.

[Action of tetracycline and rifampicin on Rickettsia prowazekii and Rickettsia sibirica].

The effect of tetracycline and rifampicin on R. prowazekii, strain Breinl and R. sibirica, strain X1 was studied in the experiments with chick embryos exposed to the antibiotic mixture with the infection material.

[Macrophage migration inhibition test in guinea pigs infected with Rickettsia prowazekii].

The process of infection caused by R. prowazekii (strain Breinl) in guinea-pigs was accompanied by the development of delayed type hypersensitivity manifested by the macrophage migration inhibition test (MMIT). This reaction could be detected on week 2 after the subcutaneous inoculation of the infective agent, achieved its maximum on weeks 3-4 with individual fluctuations taken into account and decreased by week 5 remaining at a low level during the whole period of the study (63 days).

Activity of macrophages from guinea pigs at various periods after infection with Rickettsia prowazeki.

The function of peritoneal macrophages from Rickettsia prowazeki-infected guinea pigs at various intervals of postinfection immunity was studied. The activity of macrophages in immunized animals was higher than in non-immunized ones; it was the highest in the period of the highest level of immunity and high levels of complement-fixing antibodies.

[In vitro study of function of macrophages obtained from intact and immune animals with experimental rickettsial infections].

The studies carried out on Rickettsia prowazekii (strain Breinl) have shown that these organisms can proliferate in the culture of guinea pig peritoneal macrophages, and the character of their development in macrophages depends mainly on the infective dose. Macrophages obtained from immune animals seem to have undergone functional transformation, thus becoming capable of destroying the infective agent. The process of the destruction of Rickettsia was more active in the presence of guinea pig immune serum.

Enzymatic activity of blood lymphocytes experimental tsutsugamushi fever in mice.

The influence of tsutsugamushi fever infection on the metabolism of blood lymphocytes of mice differing in susceptibility to Rickettsia tsutsugamushi and of rifampicine and tetracycline treatment was studied. In susceptible mice, the activity of oxidation-reduction processes in lymphocytes increased at 7--10 days of the disease and became normal upon recovery of the animals. In mice with low susceptibility this increase of the activity began and terminated much earlier, at 3--5 days.

Cytological investigation of Rickettsia tsutsugamushi infection of mice with different allotypic susceptibility to the agent.

Cytological and cytochemical studies on Swiss and random-bred white mice susceptible to Rickettsia tsutsugamushi infection as well as resistant C57 Black 6 and CBA mice revealed a clear-cut relationship between the severity of infection and the pattern of macrophage reaction. In highly susceptible mice the fatal infection was accompanied by death of macrophages and necrotisation of the peritoneal exudate cells. The resistant mice showed no clinical signs but developed an intensive macrophage reaction, and the main mass of the inoculated rickettsiae died at the inoculation site, the macrophages remaining viable.

Different allotypic susceptibility of mice to Rickett-sia tsutsugamushi.

Some lines of mice and random-bred mice show different susceptibility to infection with Rickettsia tsutsugamushi, displayed mainly in the development of overt infection. The latter is most markedly manifested in random-bred and Swiss mice, causing high death rates and massive accumulation of rickettsiae in the peritoneum. Black mice respond to inoculation with asymptomatic infection with no microscopically detectable rickettsiae.