[Changes in the indices of the immunogenic activity of influenza A/Hong Kong virus in the 1969-1980 epidemics]. / Izmeneniia pokazatelei immunogennoi aktivnosti virusa grippa A/Gonkong v period épidemii 1969-1980 gg.

The study of immunological changes in convalescents after influenza aged 7-12 months and 18-23 years was carried out in the period of circulation of influenza A/Hong Kong virus and its antigenic variants (1969-1980). A continuous decrease of the immunogenic activity of the causative agents of repeated epidemics and the intensity of the acquired immunity in adult convalescents was demonstrated in successive epidemics of influenza A/Hong Kong. This regularity was fully confirmed in groups of 7 - 12-month-old infants without previous exposure to influenza infection who experienced the disease. Marked differences in the incidence and clinical severity of earlier and later epidemics of influenza A/Hong Kong and changes in immunogenic activity suggest that they are associated with different virulence of the causative agents at different periods of a general pandemic cycle.

[Comparative indices of the formation and protective activity of antibodies during Honk Kong influenza A epidemics]. / Sravnitel'nye pokazateli formirovaniia i zashchitnoi aktivnosti antitel v period épidemii grippa A/Gonkong.

In the period of circulation of influenza A/Hong Kong (H3N2) virus and its antigenic varieties in 1969-1976, more than 45,000 serum specimens from patients, donors, and subjects of various ages from permanently observed contingents were examined serologically by HI and CFT. The long persistence in the human population of heterologous immunity to viruses of new or old subtypes was shown to be due to its constant stimulation in the period of any subsequent influenza A epidemic. Under conditions of a natural epidemic process as well as in the studies of the epidemiological effectiveness of live influenza vaccines the protective role of not only homologous but also heterologous (although to a lower extent) antibody was confirmed. The protective role of heterologous antibody decreased gradually with progressive variability of influenza A virus.

[Comparative characteristics of influenza type A infection in adults and children during epidemics and interepidemic periods]. / Sravnitel'naia kharakteristika grippoznoi infektsii tips A u vzroslykh i detei v épidemicheskii i mezhépidemicheskii periody.

Parallel serological examinations by CFT and HI test of paired sera from 18,557 patients and normal subjects in the period of influenza A/Hong Kong (H3N2) subtype virus in 1969-1976 revealed similar sensitivity of both methods for influenza diagnosis during epidemics, however in the interepidemic periods in these years the CFT was found to be more sensitive than HI. This observation referred to all age groups of the examined subjects with manifest or asymptomatic forms of influenza infection. In the interepidemic periods the rate of influenza in children was 6-8 times higher than that in adults. A sharp reduction in the HI sensitivity in the interepidemic periods indicates biological differences in influenza viruses circulating in these months of the year associated with clinical, epidemiological, and immunological features of influenza in the interepidemic period.

[Reproductive activity of the influenza A virus in the splenocytes of experimental animals with mono- and mixed infections]. / Reproduktsionnaia aktivnost' virusa grippa A v splenotsitakh éksperimental'nykh zhivotnykh pri mono- i smeshannoi infektsii.

Virus-induced processes in organs and tissues of Syrian hamsters in relation to the influenza A virus strain used (HON1 or H3N2), age of the animals, and in the presence of mixed infection were compared. The infection of young hamsters with A/PR8/34 and A/Bangkok/1/79 viruses was shown to induce the synthesis of viral proteins NP and M in spleen cells lasting for up to 15 days (the observation period). In mixed influenza and respiratory syncytial virus infection the possibility of influenza virus genome expression did not change. After infection of mature hamsters, synthesis of virus-specific NP and M proteins in splenocytes was observed only in the animals infected with influenza A/PR8/34 virus but not in those infected with the less pathogenic influenza A/Bangkok/1/79 virus.

[Features of primary structure of genes and proteins from passaged variations of measles virus]. / Osobennosti pervichnoi struktury genov i belkov passazhnykh variantov virusa kori.

Primary structure and proteins of measles virus variants passaged in tissue culture were studied. The findings suggest that genetic determinants responsible for measles virus attenuation are not linked with the genes coding for envelope proteins and nucleoprotein of this virus. However the detected nucleotide substitutions can be considered as the main prerequisites for the appearance of mutations in other regions of viral genome, leading to decrease of virulence for humans.

[Biological characteristics of epidemic and interepidemic strains of the influenza A (H3N2) virus]. / Biologicheskie osobennosti épidemicheskikh i mezhépidemicheskikh shtammov virusa grippa A (H3N2).

Comparative studies of biological properties of influenza A (H3N2) viruses isolated in the epidemics of 1980 and 1983 and in the interepidemic period of 1982 showed a sharp reduction of the biological activity of the interepidemic viruses as compared with that of the epidemic ones. This was manifested by low isolation rate of virus in the interepidemic period, reduced hemagglutinating, interfering, and immunogenic activity of these viruses, poor reproduction in the lung tissue of white mice and the lack of virus-specific syntheses in splenocytes of infected Syrian hamsters. Unlike epidemic strains, the interepidemic strains had ts mutation in gene 6 coding for neuraminidase. There are reasons to associate the observed defect in gene 6 with frequent development of asymptomatic forms of influenza infection in the interepidemic period.

[Antigenic drift of current influenza A viruses]. / Antigennyi dreif sovremennykh virusov grippa A.

The results of virological and serological study of the influenza epidemic of 1976 revealed a further antigenic drift of hemagglutinin and neuraminidase in current influenza A viruses. One of the features of the A/76 epidemic strains was a marked weakening of antigenic relationships with viruses of the A/Port Chalmers group and a marked relation to chronologically more remote ancestor of the current epidemic subcycle, A/Victoria/72 virus. This gives grounds to consider the new viruses to be the progeny of the latter and not of A/Port Chalmers/73 viruses. The strains of influenza A virus isolated 1 1/2-2 months before the outbreak (November-December, 1975) were typical members of the A/Port Chalmers group and differed markedly from the agents in the epidemic of 1976. This evidence indicates the exogenic, imported origin of the causative agents of the influenza epidemic in 1976 in the USSR.

[Production and testing of lyophilized standard preparation for diagnosis of Mycoplasma pneumoniae infection by the indirect hemagglutination test]. / Prigotovlenie i ispytanie liofilizovannogo standartnogo preparata dlia diagnostiki v reaktsii nepriamoi gemaggliutinatsii Mikoplazmy pnevmonii.

A method for production of a reference lyophilized preparation for diagnosis of Mycoplasma pneumonia infections in the indirect hemagglutination (IHA) test has been developed. The method is based on conjugation using bi-diasotized benzidine of acrolein-treated sheep erythrocytes and ultrasonicated whole Mycoplasma antigen. After lyophilization the diagnostic preparation retained its standard properties for 1.5 years (the observation period). The sensitivity of the preparation in detection of antibody exceeded those of the CFT and the metabolism inhibition (MI) test 16--64-fold and the specificity was as good as in these tests. The diagnostic value of the preparation in the IHA was 78.1%, in the CFT--64.7%. As compared with the CFT and the MI test, the IHA with Mycoplasma diagnostic preparation is simple and reproducible.

[Characteristics of the causative agents of the influenza A (H3N2) epidemic in Leningrad in 1983]. / Osobennosti vozbuditelei épidemii grippa A (H3N2) v Leningrade v 1982 g.

Investigation of influenza A (H3N2) epidemic of 1983 in Leningrad revealed simultaneous circulation of 3 antigenic variants similar to A/Bangkok/1/79, A/Bangkok/2/79, and A/Philippines/2/82 with significant predominance of the first antigenic variant. The viruses related to A/Philippines/2/82 comprising one-third of all isolations produced antibodies of a wide spectrum unlike the other two variants whose antisera neutralize actively the homologous virus only. The possibility of selecting epidemic strains of the A/Philippines/2/82 variety as vaccine strain candidates is discussed.

[Serological foundation for the persisting circulation of influenza viruses A(HON1) and A(H2N2) among children]. / Serologicheskoe obosnovanie prodolzhaiushcheisia tsirkuliatsii sredi detei virusov grippa A(HON1) i A(H2N2).

Examinations by the HI test of 652 sera from children aged from 9 months to 13 years revealed antibodies to A/Singapore/1/57 (H2N2) in 0.9% and A/PR/8/34 (H0N1) in 1.2% of the children. The specific nature of the activity of the sera was proved by neutralization tests and by treatment of the sera with Staphylococcus aureus adsorbing IgG class antibodies. Antineuraminidase antibodies to these viruses were also detected. Examinations of 247 paired sera from children revealed seroconversion to hemagglutinin and neuraminidase of A/Singapore/1/57 and A/PR/8/34 in 2% and 0.4%, respectively. These results testify to continuing circulation in the human population of influenza A virus subtypes of no current epidemiological importance.

[Effect of influenza epidemics on acute respiratory morbidity of noninfluenzal etiology]. / Vliianie épidemii grippa na zabolevaemost' ostrymi respiratornymi zabolevaniiami negrippoznoi étiologii.

The use of correlation analysis has made it possible to reveal a high degree of influence exerted by influenza epidemics on morbidity rate in adenoviral, respiratory-syncytial, parainfluenza and mycoplasmic infections among the population. During the months of influenza epidemic considerable concomitant incidence of respiratory-syncytial, adenoviral and especially mixed infections was observed in all age groups in comparison with periods free from influenza epidemic. The study of concomitant morbidity during the periods of 6 influenza A (H3N2) epidemics and 3 influenza B epidemics has shown that the immunosuppressive activity of influenza virus, leading to the activation of other causative agents of acute respiratory diseases, reaches its highest level at the periods of influenza A epidemics characterized by a more intensive and severe clinical course of the disease, such as in influenza A/Victoria/35/72 (H3N2), and drops to a minimum at the periods of influenza B epidemics.

[The pathomorphological changes in the brain and internal organs in experimental influenza infection in mice]. / Patomorfologicheskie izmeneniia v golovnom mozge i nekotorykh vnutrennikh organakh pri éksperimental'noi grippoznoi infektsii u myshei.

The possibility of long persistence of influenza virus A in the brain and other organs of mice was established on the basis of complex virological, histological and electron microscopic studies. It was shown that the perivascular oedema of choroid plexus reaches the maximum during late stages of infection, after the clinical recovery. Sharp increase of the permeability of cerebral vessels causing the perivascular oedema, especially in choroid plexus of lateral brain ventricles, proposed to be one of possible mechanisms of pathogenic action of the virus.

[Properties of current influenza A (H1N1) virus strains and the characteristics of the epidemics they induce]. / Svoistva sovremennykh shtammov virusa grippa A (H1N1) i osobennosti vyzvaemykh imi ípidemii.

Three epidemics of influenza A (H1N1) occurring in 1977, 1979 and 1981 were studied. These epidemics were found to be gradually dying down, which was manifested by progressively decreasing morbidity rate, the frequency and intensity of seroconversions, as well as by a decrease in the duration of the epidemic period. Changes in the biological properties of influenza A (H1N1) virus were accompanied by changes in its antigenic properties. The drift of neuraminidase in the influenza A (H1N1) virus of 1981 towards increased relationship with neuraminidase in the virus of 1952 was observed, while hemagglutinin in the strains of each of these two groups retained its individual character.

[Etiological characteristics of influenzal diseases in children's collectives under long-term observation]. / Osobennosti étiologii grippoznykh zabolevanii v dlitel'no nabliudaemykh detskikh kollektivakh.

As the result of epidemiological and virological observations, the factors which determined the duration of carriership at the period of mixed influenza A and B epidemic were established. Most children released influenza virus A for 7-9 days and influenza B virus for 10-12 days. The duration of carriership in children depended on their age, the level of humoral antibodies in their sera taken before the disease and the manifestation of their immune reaction to influenza virus infection.

[Morphologic and biochemical changes in brain cells of mice with influenza]. / Morfologicheskie i biokhimicheskie izmeneniia v kletkakh golovnogo mozga myshei pri grippoznoi infektsii.

The influence of influenza virus infection on the brain cells was studied in mice. Virology, electron microscopy and biochemistry methods were used for this purpose. It has been shown that intracerebral injection of pathogenic strain of influenza virus A/PR/8/34 is accompanied both by the reproduction of virus in the central nervous system tissue and the morphology changes in ependial cells of the vascular plexus of the brain lateral ventricle. It has been found that the level of the lipid peroxidation products in lipid extracts of infected mouse brain is greater than their level in extracts from control mouse brain. It has been concluded that the influenza virus has a damaging effect on the central nervous system cells.

[Biochemical and morphological changes in the neuroglia in experimental herpetic encephalitis]. / Biokhimicheskie i morfologicheskie izmeneniia v neiroglii pri éksperimental'nom gerpeticheskom éntsefalite.

The complex virological, biochemical and morphological study permitted to obtain various characteristics of mice herpes encephalitis. The reaction of astrocyte glia at different stages of herpes encephalitis was revealed and analyzed in detail. New data on the dynamics of desoxyribonuclease activity changes in neuroglia and the glial complex formation were obtained. It was shown that the increased DNA-ase activity in neuroglia and the astrocyte activation which morphological manifestation was the formation of glial complexes, may be referred to as processes dealing with barrier and elimination neuroglia functions in herpes encephalitis. The results presented allows to suppose that the severity of the development and outcome of herpes encephalitis mainly depends on the astrocyte glia condition, its potential abilities in appearing of barrier and eliminative functions.

[Effects of nitroxyl radicals on pathogenic properties of herpesvirus (the spin-label technique in the study of virus-macrophage interactions)]. / Vliianie nitroksil'nykh radikalov na patogennye svoistva virusa Gerpesa (metod spinovogo zondirovaniia v issledovanii vzaimodeistviia virus-makrofag).

The effect of various concentrations of both methyl ether of 5-doxyl-stearic acid (M5DS) and 4-maleimido-TEMPO (4MT) on the pathogenicity of herpes simplex virus (HSV-1) was studied. It is known that the reagents modify the lipid matrix and the proteins of virion envelope. The decrease of the HSV-1 pathogenicity was shown when using the concentration of reagents more 5 x 10(-5) M. HSV-1 having high pathogenicity and cytotoxicity was obtained when the concentrations of the reagents were less 5 x 10(-5) M.