[Comparison of in vitro and in vivo methods of evaluation of the efficacy of influenza virus hemagglutinin inhibitors].

One of the problem in the selection of the most effective antiviral preparations with a broad spectrum of antiviral protective activity, is the "continuity" of assays of different level of complexity so, that the most effective antiviral therapeutic, selected by in vitro assays would be the most effective in vivo. Comparative study of the efficacy of the influenza virus inhibitor in the assays of inhibition of virus binding with fetuin, inhibition of infectious focus forming units in MDCK cells, inhibition of virus yield in infected MDCK cells, and inhibition of influenza virus infectivity in mice infected by viral aerosol are presented. The value of 50% inhibiting concentration IC50 for the pare "influenza virus strain A/NIB/23/89-MA-inhibitor tetra-Aca6-6'SLN" corresponded to 6-10 microM and was invariant for three different tests--in vitro assay of inhibition of virus binding with fetuin, inhibition of yield in infected MDCK cell culture, and inhibition of virus infectivity in mice, but not for the assay of inhibition of infectious focus forming units in cell culture.

[Antiviral activity of oral ultralow doses of antibodies to gamma-interferon: experimental study of influenza infection in mice]. / Protivovirusnaia aktivnost' sverkhmalykh doz antitel k gamma-interferonu pri peroral'nom vvedenii: éksperimental'noe issledovanie grippoznoi infektsii u myshei.

Course intragastric administration of ultralow doses of human gamma-interferon antibodies (ULD anti-IFN-gamma) to intact mice resulted in an increase of endogenous IFN-gamma production by the animal lymphocytes. Oral prophylactic administration of ULD anti-IFN-gamma significantly lowered the influenza virus concentration in the animal lungs at the initial stage of the aerogenous infection: in 2 (p = 0.05) and 3 (p = 0.07) days after the contamination. The therapeutic antiviral effect of ULD anti-IFN-gamma in mice with influenza was evident from a significant decrease of the influenza virus concentration in the lungs of the animals on the 4th (p = 0.05) and 5th (p = 0.07) days after the contamination. The antiviral effect of ULD anti-IFN-gamma after the prophylactic and therapeutic use is likely provided by induction of endogenous IFN-gamma.

[Mechanisms of mice resistance to influenza virus A/AICHI/2/68 after preventive injection with polyprenols ]. / Mekhanizmy rezistentnosti myshei k virusu grippa A/AIChI/2/68 pri profilakticheskom vvedenii poliprenolov.

Preventive effect in influenza can be attained by intramuscular injections of fir (Abies) polyprenols. One of 5 tested polyprenol preparations (No. 1), injected 2 days before aerogenic infection with influenza virus, reliably protected mice from disease. Mice pretreated with polyprenol preparations or Hanks' solution did not differ by accumulation of interferon in the lungs One day after aerogenic infection. Three days after injection of polyprenol preparation No. 1 the weights of the spleen and thymus significantly decreased. One day after injection cell count in the bronchoalveolar tract of mice was almost 2-fold higher than in the control at the expense of lymphocytes and macrophages. After 3 days the relative and absolute counts of macrophages decreased and those of lymphocytes decreased significantly. Three days after injection macrophages were 2-fold more active in absorption of zymosan granules. Preparation No. 1 affected the production of superoxide anion radicals, whose production by all macrophages in the bronchoalveolar tract of mice was significantly higher on day 1 postinjection than on day 3 and higher than on days 1 and 3 after injection of preparation No. 2.

[Mechanisms of action of aerosol preparations based on Abies siberica polyprenols in experimental influenza infection]. / Mekhanizmy deistviia aérozolei preparatov na osnove poliprenolov pikhty sibirskoi pri éksperimental'noi grippoznoi infektsii.

Humoral and cellular mechanisms of Abies sibirica polyprenol effects on nonspecific resistance of mice to influenza A/Aichi/2/68 virus were investigated. Two aerosol doses of polyprenols had a high protective effect in mice challenged with influenza virus. Aerosol polyprenol preparations in the studied doses induced no interferon or tumor necrosis factor production in the lungs. Lung macrophage counts and capacity to produce superoxide anion radicals increased in survivors after influenza in comparison with intact animals. Double aerosol administration of polyprenols prior to influenza infection promoted an increase in the thymus weight, bronchoalveolar tract cell counts (predominantly at the expense of lymphocytes), and of superoxide-producing potential of macrophages, which, in turn, can contribute to improvement of the defense potential of the organism towards influenza virus.

[Sensitivity of white mice to influenza virus (A/Aichi/2/68) in aerogenic infection]. / Chuvstvitel;nost' belykh myshei k virusu grippa (A/Aichi/2/68) pri aérogennom zarazhenii.

Polydispersed aerosols from allantoic fluid of chick embryos induced with influenza virus with different median weight aerodynamic diameters of corpuscles (0.5, 0.8, 1.1, 2.2, and 6.0 mu are effectively deposited in respiratory organs of mice weighing 18-19 g. The sensitivity of mice of different weight to aerogenic infection with influenza virus (strain A/Aichi/2/68) was virtually the same. The efficacies of aerogenic 50% infective and lethal doses (1.8-2.5 lg) for mice of the same weight were different. The sensitivity of mice to aerogenic infection and of developing chicken embryos to the virus (ID50 = EID50) is the same. Mice weighing 10-19 g can be infected via airways with adapted influenza virus in studies of therapeutic and prophylactic effects of drugs.

[Modification of mouse resistance to A/Aichi/2/68 influenza virus by a glucocorticoid immunosuppressant kenalog]. / Izmenenie ustoichivosti myshei k virusu grippa A/AIChI/2/68 pod vliianiem gliukokortikoidnogo immunodepressanta kenaloga.

Changes in the virulence of influenza virus A/Aichi/2/68 LD50 were studied in albino mice with immunosuppression induced by long-acting glucocorticoid kenalog (Kn). In high doses (5 and 10 micrograms/g) Kn induced a decrease in the adrenal, thymic, and splenic weight, which is typical of steroid immunosuppression. The susceptibility of mice preinjected with Kn to the virus increased more than ten-fold, judging by a decrease in LD50. The detected shifts may be due to disorders in lung tissue resistance and reactivity of alveolar macrophages and neutrophils observed previously in induced glucocorticism.

[Dynamics of interferon induction in albino mice by interferon inducer ridostin administered by various routes]. / Izuchenie dinamiki interferonoobrazovaniia v organizme belykh myshei pri razlichnykh putiakh vvedeniia induktora interferona ridostina.

The time dependence of interferon production in blood, tissues of the respiratory tract, brain and olfactory tract of mice BALB/c was investigated after administration of the interferon inductor ridostin by various routes. Intraperitoneal injection of ridostin in a dose of 5 mg/kg induced intensive accumulation of interferon in the blood serum with the peak in 8 hours (2560 U/0.2 ml) while no interferon was detected in the tissues of the respiratory tract and brain of the animals. Intracerebral injection of ridostin in the same dose induced accumulation of interferon in both the tissues of the brain (maximum 160 U/0.2 ml in 24 hours) and the blood serum (maximum 1280 U/0.2 ml in 8 hours). After respiratory administration of ridostin interferon was detected only in the site of the administration in the tissues of the upper respiratory tract and lungs of the mice.

[Some aspects of interferon formation in white mice]. / Nekotorye aspekty interferonoobrazovaniia v organizme belykh myshei.

White mice weighing 14-16 g were intranasally infected with LD50 of influenza virus (A/Aichi/2/68 strain). High levels both of virus and interferon were detected in the lung. Sufficient virus accumulation in the nasal cavity occurred with low interferon induction. At the same time high blood interferon levels corresponded to sporadic low viremia. Intraperitoneal injection of the interferon inducer ridostin (a pharmacological formulation of dsRNA) to BALB/c mice (18-20 g) in a dose of 5 mg/kg induced intensive blood accumulation of interferon with its peak at 8 hours postadministration (2560 U/0.2 ml), but interferon was not detected in the respiratory tract and brain of these mice. Intranasal (15 mg/kg) and aerogenic (0.4-0.6 mg/kg) administration of ridostin induced interferon mainly in the upper respiratory tract and lung. The regularities found are in agreement with the data on interferon induction by other dsRNA preparations, which makes it necessary to design dosage forms of interferon inducers for respiratory application in influenza.

[Some pathogenetic characteristics of influenza infection in white mice]. / Nekotorye patogeneticheskie kharakteristiki grippoznoi infektsii u belykh myshei.

Influenza virus strain A/Aichi/2/68 replicated only in the lungs, nasal cavity, and trachea after intranasal challenge of white mice weighing 14-16 g. Rapid accumulation of the virus was associated with a somewhat delayed accumulation of endogenous interferon in the lungs, the concentration of interferon gradually decreasing by the end of the disease. An appreciable accumulation of the virus in the nasal cavity was coupled with weak interferon induction in this organ. On the other hand, a high level of interferon in the blood was concomitant with the development of slight sporadic viraemia.

[Study of the treatment-prophylactic effect of immunomodulators in experimental infections, caused by Marburg, Ebola, and Venezuelan equine encephalitis viruses]. / Izuchenie lechebno-profilakticheskogo deistviia immunomoduliatorov pri éksperimental'nykh infektsiiakh, vyzvannykh virusami Marburg, Ebola i Venesuél'skogo éntsefalomielita loshadei]

Therapeutic and prophylactic effects of immunomodifiers ridostin, reaferon, and polyribonate used alone and in various combinations were assessed in experiments on guinea pigs infected with Venezuelan equine encephalomyelitis (VEE) (strain Trinidad), Marburg (strain Popp), and Ebola (M/C-8 variant of Zaire strain) viruses at doses 5 to 20 respiratory LD50 through the respiratory airways. Urgent prophylactic simultaneous intramuscular and intranasal administration of ridostin protected the animals infected with Marburg virus (p = 0.1) and prolonged their life span by 2.4 days (p = 0.15). In Ebola infection a combination of ridostin and reaferon appreciably prolonged the mean life span: by 2.9 days (p = 0.04). In VEE ridostin alone or in combination with reaferone appreciably increased the share of survivors; ridostin with reaferon and polyribonate notably prolonged the mean life span of infected animals. None of these drugs or combinations produced an appreciable therapeutic effect in any of the studied infections.

[Prediction of the epidemiological efficiency rate of preventive antiviral drugs from laboratory findings]. / Prognozirovanie koeffitsienta epidemiologicheskoi effektivnosti profilakticheskikh protivovirusnykh preparatov po dannym laboratornykh issledovanii.

Based on the dose-response dependence represented as a generating distribution function of infecting doses of a pathogen, a value for the epidemiological efficiency rate of preventive agents was derived. For an arbitrary distribution of infecting doses, EEC mean values is shown to always no greater than 1: ED50v/ED50w where ED50v and ED50w are 50% of the infective doses of the pathogen assessed for those treated with the agent and intact persons, respectively. This relation is also valid when differences in pathogenic resistance are determined not only due to the use of drugs, but for any other variables (age-, sex-specific and other factors). This was verified by experiments.

[Certain pathogenetic characteristics of a disease in monkeys in infected with the Marburg virus by an airborne route]. / Nekotorye patogeneticheskie kharakteristiki zabolevaniia obez'ian, aérogenno infitsirovannykh virusom Marburg.

Time course of Marburg virus (strain Popp) accumulation and changes in hematological parameters were studied in aerosol infected M.rhesus monkeys. The lungs were the first organ in which the virus was detected after respiratory infection of monkeys. Four days after inoculation the virus was detected in the liver, spleen, blood, and thymus. Six days after inoculation the virus was present in virtually all organs and secretions. The period of fever was associated with manifest leukopenia in primates. Blood clotting time drastically increased by the moment of animal death.

[Experimental Ebola fever in Macaca mulatta]. / Eksperimental'naia likhoradka ébola u makak rezusov.

Aerogenic infection of M. rhesus with Ebola virus causes in them a disease similar in the principal clinical and virological parameters a grave form of Ebola fever in humans, as it is described in literature. Rapid development of symptoms of total intoxication in the presence of fever, hemorrhagic diathesis, and high viremia are indicative of the infection severity in monkeys.

[Clinical-virusological characteristics of disease in guinea pigs, infected by the Marburg virus aerogenically]. / Kliniko-virusologicheskie kharakteristiki zabolevaniia morskikh svinok, aerogenno infitsirovannykh virusom Marburg.

Marburg virus (strain Popp) was found to accumulate in various organs of guinea pigs after aerogenic infection. At the initial stage of the infection primary multiplication of the virus took place in the lungs. The presence of the virus in bronchopulmonary washings 2-3 days after infection, leukopenia and hyperthermia 4 days after infection are the earliest virological and clinical signs of disease in aerogenically infected guinea pigs.

[The efficacy of the emergency prophylactic and therapeutic actions of immunomodulators in experimental filovirus infections]. / Effektivnost' ékstrenno-profilakticheskogo i lechebnogo deistviia immunomoduliatorov pri éksperimental'nykh filovirusnykh infektsiiakh.

The study of the preventive and therapeutic action of some immunomodulators (ridostin, reaferon and polyribonate) used alone and in combinations was conducted on laboratory animals infected aerogenically by Marburg or Ebola virus. It was found that special preventive intranasal and intramuscular administration of ridostin provided protection of the animals infected by Marburg virus (p = 0.1) and an increase in their mean lifespan by 2.4 days (p = 0.15). In the Ebola infection combined administration of ridostin and reaferon caused an essential increase in the mean lifespan of the animals by 2.9 days (p = 0.04). None of the tested drugs had any significant positive effect when used in various combinations according to the treatment schemes in Marburg and Ebola infections in guinea pigs.