[Changes in the properties of the vaccinia virus isolated in postvaccinal encephalitis].

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).

Immune response to different tick-borne encephalitis vaccines as revealed by lymphocyte blast transformation and virus neutralization tests.

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.

[Current problems of immunoprophylaxis of infectious diseases and standardization of medical immunobiological preparations].

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.

[Pathogenesis of an infection induced in Syrian hamsters by attenuated strains of viruses of the tick-borne encephalitis complex].

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.

Blastogenic lymphocyte response as indicator of cell-mediated immunity in humans vaccinated with live and inactivated influenza vaccines.

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.

A study of candidate rabies vaccines for a national reference preparation for the evaluation of antigenic potency.

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).

[Long-term persistence of the vaccinia virus in a child with a congenital skin disease].

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.

[Course of the vaccinal process induced by the vaccinia virus in cyclophosphane-suppressed cellular and humoral immunity].

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.

[Evaluation of the toxic action of prophylactic and therapeutic preparations on cell cultures. III. The detection of toxic properties in medical biological preparations by the degree of cell damage in the L132 continuous cell line].

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.

[Immunodepressive action of vaccinia virus].

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.

[Attenuated variants of the tick-borne encephalitis virus complex].

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.

[Cellular and humoral immunity studies after vaccination against influenza].

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.

[Use of a cocultivation method for detecting cytomegalovirus contamination of cell cultures of simian origin].

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.

[Blast transformation reaction of the peripheral blood lymphocytes from persons inoculated with a tick-borne encephalitis vaccine].

The indices of blast transformation of lymphocytes to polyclonal mitogens of phytohemagglutinin (PHA) and Pokeweed mitogen (PWM) and to tick-borne encephalitis virus antigen (TBE) were studied in 80 individuals in the course of vaccination against tick-borne encephalitis. In the time course of vaccination reactions of blast transformation of lymphocytes was found to decrease to PHA and to increase to TBE and PWM antigens; spontaneous blast transformation also increased. Increased blast transformation reaction to TBE and PWM antigen correlated with the results of serological studies.

[Results of a study of the pathogenesis of postvaccinal encephalitis].

The results of 10-year virological and immunological studies in patients with postvaccination encephalitis (PVE) developing after smallpox vaccination are analysed. Vaccinia virus was isolated from 23 (59%) out of 39 children in the acute stage of PVE and for a long period in the protracted course of the disease in 14 out of 24 from the cerebrospinal fluid in 15 out of 33 from the blood, in 8 out of 24 from the throat and in 4 out of 5 from the brain or spinal cord tissue. Examinations of 56 serum specimens from 36 children with PVE revealed considerable variations in the levels of virus-neutralizing antibodies (VNA): 6 had no VNA, while 10 children showed low titres (10-20).

[Effect of small doses of diphtheria exotoxin on cell cultures].

High diphtheria exotoxin concentrations induced irreversible injuries to all the cultures under study (L, HeLa, spcv pzM). However, its final titres in the mentioned cells differed. HeLa and pzM cells, being highly sensitive, can be recommended for titration of dipheria exotoxin, instead of the expensive guinea pig tests.