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Properties of 6 isolates of vaccinia virus isolated from the brain and cerebrospinal fluid in postvaccination encephalitis were studied in comparison with 2 production strains of vaccinia virus with which the children had been vaccinated. Significant differences were found between the strains isolated in postvaccination encephalitis and reference virus strains. The plaques produced by the isolates from brain and CSF were larger (and in some isolates had a hemorrhagic pattern). The isolates were highly pathogenic for chick embryos, reproduced more actively in cells of the chorioallantoic membrane of chick embryos at higher temperature of incubation (40 degrees C), more intensively accumulated in the liver and brain of chick embryos at 37 degrees C and 40 degrees C, produced more intensive lesions and necroses in rabbit skin. The isolates were markedly thermostable at 56 degrees C and insensitive to interferon. It is suggested that the increased pathogenicity of the virus is manifested in the presence of altered immune responsiveness of the host.

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Immunological memory has been demonstrated in lymphocytes of persons vaccinated against tick-borne encephalitis (TBE). Stimulation indices (SI) of lymphocytes in response to TBE virus antigens in lymphocyte blast transformation test increased after complete vaccination course with the commercial vaccine; by this time, sera of vaccinees contained virus neutralizing antibodies. The concentrated purified vaccine had a higher immunogenic activity, as evidenced by increased SI and virus neutralizing antibodies (NA) in the vaccinated subjects already after the first and second vaccinations.

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The state of immunoprophylaxis in the whole of the USSR and in individual Union Republics in 1981-1982 is ralyzed. The connection between an increase in diphtheria, pertussis and measles morbidity and the widening of the scope of contraindications to vaccination has been revealed. The optimum vaccination tactics in Union Republics with regard to differences in their climatic conditions and demographic situation is planned. The problems of the standardization of prophylactic and therapeutic immunobiological preparations are considered. Organizational measures leading to the improvement of their quality are outlined.

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The level and dynamics of lymphocyte blastogenesis in response to phytohaemagglutinin (PHA) and to specific influenza virus antigen were studied in 3 groups of humans, vaccinated with live or inactivated whole virion influenza vaccines (H3N2 type) and placebo (control group). Both live and inactivated influenza vaccines did not change significantly the functional activity of T lymphocytes as determined by the mean values of stimulation index (SI). The analysis of individual values of PHA-dependent blastogenic response, however, revealed a decrease in SI as compared with its prevaccination level in 33.3 +/- 11.4% of the vaccinees given the live influenza vaccine.

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The results of virological and morphological study of the pathogenesis of the infection induced by viruses of the tick-borne encephalitis complex (attenuated TP-21 and E-30 strains) in Syrian hamsters with normal and suppressed immune response are presented. The data obtained indicate long-term persistence of the virus-specific antigen: sufficiently high titres of specific antibodies in the blood serum of the animals at late periods after virus inoculation, positive immunoenzyme tests for virus antigen in the meninges of the hamsters inoculated with the TP-21 strain. Features of the pathogenesis were found to be related to strain characteristics, particularly the degree of their attenuation. Chronic destructive process and reparative gliosclerosis were observed in the CNS of some animals due to Protozoa of the genus Encephalitozoon; in this connection, the necessity of differential diagnosis between cuniculosis and a process of virus genesis is emphasized.

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An unconcentrated and a concentrated lot of rabies vaccine prepared in Syrian hamster kidney cell culture from the Vnukovo-32 strain have been examined for their suitability as national reference preparations for rabies vaccine. The antigenic potencies of the preparations were assessed by the NIH test using both fixed and street strains of rabies virus and by the method of antibody induction. The candidate vaccines were calibrated in comparative assays with the WHO 3rd International Reference Preparation of Rabies Vaccine (IRP3). The correlation between the level of virus-neutralizing antibody and the resistance of mice to intracerebral challenge with a fixed rabies virus strain was studied. The candidate vaccines were also examined by the thermal degradation test. It was found that both vaccines had appropriate antigenic potency and thermostability to be used as a national reference preparation of rabies vaccine.

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Under conditions of immunosuppression of B- and T- cell function by cyclophosphane the vaccination process in mice immunized with vaccinia virus was considerably more severe than in the untreated animals: mortality in immunosuppressed mice was much higher than in the controls; the virus could be isolated from their lungs for longer periods and in higher titres; the number of antibody-producing cells in the spleen and antibody levels in the blood were lower. In contrast to the inactivated vaccine, live vaccine itself exerted a marked immunosuppressive effect.

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Persistence of vaccinia virus which was isolated many times from the blood and skin lesions was discovered in a child vaccinated 6 years before against smallpox and suffering from bullous epidermolysis. The level of immunoglobulins A, M, and G was normal, whereas the titre of virus-neutralizing antibodies against smallpox was low (1:10) in the child, and reached 1:320 in his mother not vaccinated against smallpox. Humoral immunity for other antigens was found to be unimpaired, the skin tests being positive. It was concluded that the child had a selective defect of the immune system. It is emphasized that the virus excretor is epidemically hazardous for subjects with skin diseases, immunodeficient conditions and others, in whom contraction of the infection may result in a disease the identification of the genesis of which would be extremely difficult against the background of discontinued vaccination against smallpox.

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The methods of the quality control of medical biological preparations, including tests on animals, do not ensure the complete absence of toxicity in a final product. The use of the method of "subcultures with the introduced preparation" makes it possible to determine the toxicity of both specific and nonspecific components of vaccines and sera from the number of dead and damaged cells. The toxic action of preparations kills and damages the cells at the site of injection, thus inducing the formation of autoantigens whose effect on the body cannot be predicted. Thus thimerosal, commonly used as preservative, has been found not only to render its primary toxic effect, but also capable of changing the properties of cells. This fact suggests that the use of thimerosal for the preservation of medical biological preparations, especially those intended for children, is inadmissible.

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The oncolytic and immunotherapeutic effect of the national BCG vaccine with respect to undifferentiated sarcoma of hamster induced by the highly oncogenic adenovirus of green monkeys SA7(C8) was studied. Preliminary data on significant positive effect of the vaccine inoculated before tumor formation were obtained. A single inoculation of the vaccine into tumors did not result in tumor regression in any of the cases.

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The hemolytic plaque test in mice was used to demonstrate that live vaccinia virus has marked immunosuppressant action. Inactivated vaccinia virus produces no such an effect and even stimulates the output of the antibody-forming cells. The experimental data were found to be statistically significant.

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The paper presents the results of the study of 8 attenuated strains of viruses of the tick-borne encephalitis complex by the marker of pathogenicity for Syrian hamsters in comparison with virulent virus strains. The group of the attenuated strains was found to be nonhomogeneous in this marker of pathogenicity for Syrian hamsters. One of the 8 strains, Pan-114, proved to be highly virulent for these animals by the intracerebral route. The analysis of the experimental results and data from the literature shows the degree of pathogenicity of attenuated strains to differ for mice, Syrian hamsters and monkeys, apparently indicating that each virus variant is attenuated only for a given species of laboratory animals.

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The indices of cellular and humoral immunity (the number of leukocytes, lymphocytes, T- and B cells, E- and EAC-RFC, blastogenic reaction of lymphocytes in response to treatment with phytohemagglutinin and influenza virus antigen in vitro, antihemagglutinin and influenza virus antigen in vitro, antihemmagglutinin titres) in humans vaccinated with different types of inactivated influenza vaccines produced in the USSR and the GDR were investigated. The immunogenic potency, general and immunological innocuity of the inactivated influenza vaccines under study and more marked stimulation of the B-system of immunity by them were demonstrated.

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At present, nonanthropoid primates are widely used as sources of cell cultures for manufacture of live viral vaccines. Simian cell cultures, particularly kidney cell cultures are also known to be frequently contaminated with cytomegaloviruses. The isolation of the latter is rather difficult due to the late appearance of the cytopathic effect in cell cultures of natural hosts. In the present study, the sensitivity of 4 methods virus isolation from the test cells was compared: the method of long-term cultivation of cells; the method of long-term cultivation with one subpassage of the cells; the method of cocultivation of the test cells by mixing with sensitive cells; and the method of co-cultivation by overlaying the test cells on an incomplete monolayer of sensitive cells. The latter method shortened the observation period and yielded a higher percentage of isolation of contaminating viruses from African green monkey kidney cell cultures. This method is supposed to be used in future for the detection of viral contamination of African group monkey kidney cell cultures utilized in manufacture of live viral vaccines.

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