[Comparative analysis of tests on in vitro and in vivo quantitative assessment of the immunogenicity of tick-borne encephalitis vaccine]. / Sravnitel'nyi analiz testov in vitro i in vivo kolichestvennoi otsenki immunogennosti vaktsiny kleshchevogo éntsefalita.

Many-year routine use of EIA as an in vitro test demonstrated it as a highly reproducible and technological test for assessing the efficacy of vaccine against tick-borne encephalitis and its semiproducts at the intermediate stages of vaccine production. The reproducibility of mouse protection test is notably inferior to that of EIA.

[The use of rocket immunoelectrophoresis for determining glycoprotein in concentrated rabies vaccines]. / Primenenie raketnogo immunoélektroforeza dlia opredeleniia glikoproteina v kontsentrirovannykh antirabicheskikh vaktsinakh.

Rocket immunoelectrophoresis (RIE) was shown to be useful for the evaluation of glycoprotein (GP) content in concentrated rabies vaccines, and disintegron B., a zwitterionic detergent made in this country, for treatment of the vaccines for these evaluations. The values of GP content obtained by RIE and single radial immunodiffusion test were similar. The highest values were obtained for all the vaccines tested with anti-PM GP serum compared with anti-ERA and Vnukovo-32 GP serum. When anti-PM and anti-Vnukovo-32 GP sera were used for RIE two components were revealed in the vaccines. All the preparations under study contained soluble GP.

[The protective activity of preparations made from the tick-borne encephalitis virus grown using different cell cultures]. / Izuchenie protektivnoi aktivnosti preparatov iz virusa kleshchevogo éntsefalita, vyrashchennogo s ispol'zovaniem razlichnykh kletochnykh kul'tur.

The preparations of tick-borne encephalitis (TBE) virus grown in swine embryo kidney cell culture have been shown to possess pronounced protective activity per unit of virion protein E in comparison with TBE virus preparations derived from cell culture 4647 and chick embryo cell culture. The antigenic activity of all virus preparations under study has proved to be practically the same. The role of post-translation modifications of TBE virus protein E in the manifestation of some of its biological properties is discussed.

[The immunogenicity of a cultured inactivated hepatitis A vaccine]. / Immunogennost' kul'tural'noi inaktivirovannoi vaktsiny gepatita A.

A trial of inactivated hepatitis A viral vaccine of heteroploid cell culture origin is described. The vaccine preparation was tested in guinea pigs and tamarins. The animals were immunized intramuscularly four or three times, respectively. The efficacy was judged by induction of anti-HAV antibody persisting for at least 12 months in guinea pigs, and development of immunity to subsequent virus challenge (monkeys only). The challenge dose of HAV was unable to produce any signs of HAV infection in the vaccinated tamarins, although the booster effect was observed in some animals. The study demonstrated that the tested batches of the vaccine were highly immunogenic.

[The process of the pH-dependent fusion of the tick-borne encephalitis virus with artificial membranes]. / Izuchenie protsessa pH-zavisimogo sliianiia virusa kleshchevogo éntsefalita s iskusstvennymi membranami.

Fusion of TBE virus with liposomes was distinctly determined at pH 7.0 or lower, the maximum degree of fusion being observed at pH 6.4. Disorders in the native structure of TBE virus envelope protein E prevented virus-membrane fusion. Pre-incubation of viral preparations at pH 6.0 completely inhibited the fusion process, while rupture of disulfide bonds in protein E reduced the degree of fusion approximately 2-fold. Reduction of TBE virus infectivity upon changes in the native conformation of protein E as a consequence of disorders in the process of fusion of virions with cell membranes is discussed.

[Immunogenicity and stability of a Soviet inactivated cultured vaccine against Japanese encephalitis]. / Immunogennost' i stabil'nost' otechestvennoi kul'tural'noi inaktivirovannoi vaktsiny protiv iaponskogo éntsefalita.

Six immunologically active vaccine batches inducing a specific antibody to Japanese encephalitis (JE) virus were obtained in serial manufacture of the preparation. In HI tests, the minimal antibody titre was 1:80, the maximal 1:320, neutralization index 1g was 3.7 to 5.2. The data on the stability of the antigenic potency of the vaccines in relation to the duration of storage at 4 degrees-6 degrees C are presented (the follow-up period 3 years). A certain relationship was found between the antigenic potency of the preparation and the titre of the initial infectious tissue culture virus. Also, a definite correlation was found between the initial immunogenic potency of the vaccines and their stability in storage. After 3 years of storage, three vaccine lots remained antigenically active, namely those which after manufacture had induced antihemagglutinins in titres 1:160 to 1:320. The antigenic activity of 6 vaccine batches prepared from the production strain Peking-1 (Nakayama serotype) was studied against the predominant strain of Jagar-10 serotype. All the freshly prepared vaccine batches were found to induce production of antihemagglutinins to both serotypes of JE virus, whereas virus-neutralizing antibodies were found only to the test strain Nakajama-NIH homologous to the vaccine Peking-1 strain. After 1 year of storage, four vaccine batches lost their capacity to induce production of antihemagglutinins to Jagar-01 strain, two batches induced antibody in low titres. This fact should be considered in evaluation of postvaccination immunity status in humans.

[The purification of tick-borne encephalitis virus preparations of cellular DNA]. / Ochistka preparatov virusa kleshchevogo éntsefalita ot kletochnoi DNK.

According to the WHO requirements, the concentration of cellular DNA in vaccine preparations produced by pooling virus from continuous cell lines is limited to 100 ng/dose. In this study, different methods were used for purification of tick-borne encephalitis virus suspensions grown in continuous cultures of cell line 4647 from cellular DNA. Two approaches are proposed based on treatment with DNAse and promamin sulfate which allow one to reduce cellular DNA concentration in the virus preparation to the acceptable level. Prospects of their use in vaccine production are discussed.

[Changes in biological properties of tick-borne encephalitis virus during cleavage of disulfide bonds in protein E]. / Izmeneniia biologicheskikh svoistv virusa kleshchevogo éntsefalita pri razryve disul'fidnykh sviazei v belke E.

The study showed the disruption of disulphide bonds in E protein of tick-borne encephalitis virus (TBE) to lead to the loss of antigenicity, infectivity, hemagglutinating and protective activities. The loss of infectivity under the effect of a thiolic reagent appears to be associated with block of the very first stage of virus-cell interaction, virus adsorption on the target cell. An attempt to reestablish the E protein structure and the above-mentioned virus properties after the removal of the thiolic reagent failed. The role of tertiary structure of E protein in the manifestation of TBE virus main biological properties is discussed.

[Use of direct solid-phase immunoenzyme analysis for assessing the immunological activity of a vaccine against tick-borne encephalitis]. / Primenenie priamogo tverdofaznogo immunofermentnogo analiza dlia otsenki immunologicheskoi aktivnosti vaktsiny protiv kleshchevogo éntsefalita.

A high correlation between the current index of the effectiveness of tick-borne encephalitis vaccine, its protective activity in mice, and the results of the direct solid-phase enzyme-immunoassay has been established, which permits the use of this assay as an auxiliary method for the immunological evaluation of newly prepared commercial purified tick-borne-encephalitis vaccine.

[Reactogenicity and antigenic activity of a chromatographic cultured purified and concentrated inactivated dried vaccine against tick-borne encephalitis]. / Izuchenie reaktogennosti i antigennoi aktivnosti khromatograficheskoi kul'tural'noi ochishchennoi kontsentrirovannoi inaktivirovannoi sukhoi vaktsiny protiv kleshchevogo éntsefalita.

The study of the characteristics of a new dried tissue-culture purified concentrated inactivated vaccine against tick-borne encephalitis, manufactured in the USSR, has revealed that the preparation is moderately reactogenic and produces no definite side effects in the vaccinees. In the process of the controlled epidemiological trial the optimum vaccination schedule for the primary immunization of adults against tick-borne encephalitis with the new preparation has been determined by the study of serum samples from the vaccinees in the hemagglutination inhibition test and the neutralization test in tissue culture. In accordance with this vaccination schedule the course of primary immunization with the chromatographic variant of the concentrated vaccine consists of two injections in a dose of 0.5 ml, made at an interval of 6 months.

[Immunity indices of mice immunized with different vaccines against Japanese encephalitis]. / Pokazateli immuniteta u myshei, immunizirovannykh razlichnymi vaktsinami protiv iaponskogo éntsefalita.

The test of adoptive transfer of immunity demonstrated that in the mice vaccinated with inactivated Japanese encephalitis vaccines the protective activity to the homologous virus is provided predominantly by B-lymphocytes the protective effect of which is enhanced by cooperative interaction with T-lymphocytes. The culture (CV) and purified brain (BV) vaccines induce high levels of humoral and cell-mediated immunity, however, the capacity of CV to produce antibody is higher than that of BV. Both preparations do not cause in vaccinated mice any changes in responsiveness to extraneous antigen (sheep red cells), or disorders in chemotaxic mobility of leukocytes and phagocytic activity of macrophages.

[Donor immunization with an inactivated concentrated purified vaccine against tick-borne encephalitis to obtain immune blood preparations]. / Immunizatsiia donorov inaktivirovannoi kontsentratrirovannoi ochishchennoi vaktsinoi protiv kleshchevogo éntsefalita dlia polucheniia immunnykh preparatov krovi.

Vaccination of seronegative and seropositive donors with a concentrated purified vaccine (CV) against tick-borne encephalitis induced antibody synthesis in a concentration sufficient for preparation of donor immunoglobulin with antibody titres of 1:320 to 1:1280 by HI test. The resulting preparation showed a high antiviral activity both in vivo and in vitro against antigenically different strains of tick-borne encephalitis virus. The immune plasma derived from CV-immunized donors had a therapeutic effect in patients with tick-borne encephalitis. The optimal schedules for immunization of donors are discussed.