[Mumps vaccine virus transmission].

In this work we report the mumps vaccine virus shedding based on the laboratory confirmed cases of the mumps virus (MuV) infection. The likely epidemiological sources of the transmitted mumps virus were children who were recently vaccinated with the mumps vaccine containing Leningrad-Zagreb or Leningrad-3 MuV. The etiology of the described cases of the horizontal transmission of both mumps vaccine viruses was confirmed by PCR with the sequential restriction analysis.

[Comparative evaluation of two enzyme immunoassays for detection of immunoglobulin G antibodies to mumps virus].

Two enzyme immunoassays (ELISA) for mumps antibody detection using the Enzygnost (Germany) and Parotit-screen (Russia) were comparatively assayed using sera of randomly assigned 70 healthy young adult volunteers. The neutralization test (NT) was performed for all sera using mumps viruses (MVs) of the relevant strains Enders and Leningrad-3. The proportion of positive results was significantly higher with the Parotit-screen than with the Enzygnost (80% versus 52.9%, p < 0.05). The proportion of the concordant results in both ELISAs was as 72.9% (50% for positive results and 22.9% for negative results). There was significantly better agreement between the NT with MV strain Enders and Enzygnost (98.6%, r = 0.9, p < 0.05) than between the NT with MV strain Leningrad-3 and Parotit-screen (77.1%, r = 0.6, p < 0.05). It was concluded that the Enzygnost was apparently more specific than the Parotit-screen.

[Comparative evaluation of Leningrad-3 mumps vaccine virus neurovirulence in a neonatal rat model].

The neurovirulence and replication potential of several mumps virus strains, including Leningrad-3 mumps vaccine virus (FSUE SIC "Microgen", Russia) and wild type strains isolated in the Novosibirsk Region (Russia), were assessed in rat tests. The mean neurovirulence scores of the Leningrad-3 virus (< 4.0) were significantly lower than those of wild type strains (ranging from 6.1 to 15.2) and were in accordance with the scores determined for other attenuated mumps vaccine strains (usually ranging from 0 to 5). In general, the relative ability of the viruses to replicate in the rat brain tracked with their neurovirulence scores. These results indicate a low neurovirulence potential of the Leningrad-3 mumps vaccine virus for humans.

[Functional state of specific immunity in children and teenagers vaccinated against mumps].

The functional state of immunity was evaluated from the avidity index (AI) of specific antibodies (IgG) and the level and spectrum of their neutralizing activity. The study recruited 200 subjects immunized with Russian vaccine against mumps according to the mandatory scheme. A group of vaccinees with a low AI of specific IgG was identified mainly among old children and teenagers. The vaccinees with a low AI had a significantly lower protective immunity (as shown from the level and spectrum of serum neutralizing activity) than those with a high AI. The vacinees with no humoral, incomplete, or complete postvaccination immunity, but with a low AI of specific IgG, can constitute a population stratum that preserves sensitivity to wild-type mumps viruses and serves as a favorable medium for their circulation.

[Virus strain specific serum neutralizing antibodies in children and adolescents immunized with a Russian mumps vaccine].

Postvaccination immunity was studied in the children and teenagers without a history of clinical mumps infection, who had been immunized with the Leningrad-3 mumps vaccine. The level of specific lgG in ELISA and that and spectrum of their neutralizing activity against a vaccine strain and three heterologous mumps virus (MV) strains (genotypes A, C, and H) were measured. The investigation included 151 sera from the vaccinees aged 3 to 17 years, possessing the detectable specific IgG titers in ELISA and the detectable neutralizing titers against the vaccine strain. 97.4% of the vaccinees had neutralizing activity against 1-3 heterologous MV strains. A preponderance of neutralizing titers against heterologous MV strains by 1-log2 in some sera (6.5-32.5 depending on age) was most likely to suggest that the vaccinees' had been in contact with these virus strains in the past. In our investigation, a combination of positive IgG titers and neutralizing titers against the vaccine strain 2-log2 or higher provided the protection of the vaccinated children and teenagers against the symptomatic infection. There was a pronounced buster effect of the second immunization and a drop in the neutralizing activity of the sera from the vaccinated children and adolescents over time after the first and second immunization.

[Comparative study of hemostasis and cytokine production in experimental Dengue virus infection].

Some parameters of hemostasis and cytokine production during the fatal and nonfatal course of experimental human versus murine infection caused by Dengue virus (DV) were studied. Its lethal dose administration induced a rapid development of anemia, thrombocytopenia and a change in packed cell volume. These changes were not so profound in the nonfatal group of infected mice. There was an excess production of both proinflammatory (TNF-alpha, IL-1beta) and anti-inflammatory (IL-6, IL-10) cytokines in the fatal group. In mice of this group, the early rise of IFN-gamma and IL-12 corresponded to the parameters observed in patients with severe forms of DV infection. The findings provide evidence that the proposed model may be used for the experimental study of the immunopathogenesis of the disease.

[Immune response in vaccinated and non-vaccinated mice infected with tick-borne encephalitis virus].

The paper deals with an investigation of an immune response in BALB/c mice immunized with tick-borne encephalitis (TBE) vaccine and infected with TBE virus and in non-immunized mice. The parameters of specific humoral (IgG and IgM) and cellular (gamma-interferon (IFN) and cell proliferation) immunities and the activity of cytokines (necrosis tumor factor-alpha, interleukin (IL)-1beta, IL-2, IL-6, IL-10, and IL-12) were studied. There were significant differences in the specific and nonspecific immune response of immunized and non-immunized animals. Noteworthy is the difference in the time course of changes in the levels of IL-6, IL-2, IL-12, and gamma-IFN in the immunized and non-immunized animals.

[An experimental study of possibility of treatment of hemorrhagic fever Marburg by Remicade]. / Eksperimental'noe izuchenie vozmozhnosti lecheniia gemorragicheskoi likhoradki Marburg preparatom Remicade.

The effect of Remicade, administered according to different schemes, produced on the course of experimental Marburg hemorrhagic fever was studied. When the drug was used from the first infection day, the treated animals died reliably earlier versus the controls (infected animals). A reliably lower concentration of TNF-alpha in blood serum (versus the controls) was registered on day 3. At the same time, when Remicade was used from day 3 after infection, a 50% survival of animals was registered. It is noteworthy, that the TNF-alpha concentration in blood serum did not differ, on day 3, from that of controls, whereas, beginning from day 5 after infection, the animals displayed a downtrend of TNF-alpha concentration. Hence, it can be an evidence of a dual TNF-alpha role in the immunopathogenesis of Marburg hemorrhagic fever: on day 1 after infection the production of TNF-alpha is needed; whereas, if there is an overproduction of the cytokine, it is necessary to inhibit it. The treatment scheme in hemorrhagic fever must, apparently, comprise both elements of cytokine therapy and drugs affecting other chains of pathogenesis--they must mainly protect the endothelial vascular cells.

[Activity of cytokines in immunization with a vaccine against experimental tick-borne encephalitis]. / Aktivnost' tsitokinov pri immunizatsii vaktsinoi protiv kleshchevogo éntsefalita v éksperimente.

An experimental double immunization of BALB/c mice with a vaccine against tick-borne encephalitis was accompanied by the production of IL-1b, IL-2, IL-4, IL-6, IL-10, IL-12, TNFa and gamma-IFN in the blood serum of animals. After the first immunization of animals with the vaccine against tick-borne encephalitis, the activity of cytokine was indicative of an activation of macrophages as well as of an activation and differentiation of T- and B-lymphocytes. After the second immunization and unlike the first one, there were changes in the production only of IL-10, IL-12 and gamma-IFN, which can be indicative of a regulation of balance between Th1 and Th2.

[Cytokine production during experimental infection of mice with tick-borne encephalitis virus]. / Produktsiia nekotorykh tsitokinov pri éksperimental'noi infektsii virusom kleshchevogo éntsefalita u myshei.

An experiment with BALB/c mice, infected with a lethal dosage of the virus of tick-borne encephalitis (TE), strain 205, was accompanied by pronounced growing concentrations of the IL-1 beta, IL-6, IL-10 and TNF alpha cytokines in the blood serum of animals. The maximum values of the above cytokines were determined at the infection terminal stage. A reliably less pronounced growth of concentrations of IL-1 beta, TNF alpha and IL-10 was found in animals infected with a non-lethal TE dosage. The concentration of IL-6 in the blood serum of animals, infected with a non-lethal dosage of the virus, changed during the whole observation period. The dynamics of cytokines in the blood serum of mice, infected with a lethal dosage of the TE virus, suggests the development of SIRS at the infection terminal stage.

[Production of immune mediators, induced by Lassa virus, in a human mononuclear cell culture]. / Produktsiia mediatorov immuniteta v kul'ture chelovecheskikh mononuklearov, indutsirovannaia virusom Lassa.

Infection of human mononuclear cells with Lassa virus leads to production of inflammatory cytokines (tumor necrosis factor and interleukin-1). These cytokines cause expression of adhesion receptors ICAM-1 and VCAM-1 by human endothelial cells. Mitogen-induced cell proliferation was not suppressed 1 h after infection of human mononuclear cells with Lassa virus in a dose of 0.01 PFU/cell. The capacity of cells to proliferation in response to mitogen stimulation decreased significantly only 4 h after infection.