[Methodological aspects of studying chemical preparations in a model of experimental influenzal infection]. / Metodicheskie aspekty izucheniia khimiopreparatov na modeli éksperimental'noi grippoznoi infektsii.

Some methodologic approaches have been developed permitting most exhaustive characterization of antiviral and antitoxic activity of drugs in mice infected with toxigenic and nontoxigenic influenza A virus strains.

[Method for the cross protection of mice in studying the antigenic variability of the influenza virus]. / Metodika perekrestnoi zashchity myshei v izuchenii antigennoi izmenchivosti virusa grippa.

A modification of the method of cross protection of mice was developed for the study of influenza virus antigenic drift. This modification does not require a pre-adaptation of the virus to mouse lungs. The experiments of cross protection of immune animals carried out by the modified method demonstrated antigenic variability of the influenza A virus strains (H3N2) isolated in 1968-1983. Immunologically significant differences between influenza A/Hong Kong/68/ and A/Victoria/36/72 virus strains were detected. Subsequently, with isolation of more influenza virus strains immunologically significant differences were found between A/Victoria/36/72 and A/Leningrad/42/75 (an analogue of A/Scotland/840/74) strains, A/Leningrad/42/75 and A/Leningrad/399/76 (an analogue of A/Victoria/3/75) strains. The differences between influenza A/Texas/1/77 and A/Leningrad/527/80 (an analogue of A/Bangkok/1/79), A/Leningrad/385/80 (an analogue of A/Bangkok/1/79), and A/Leningrad/50/83, (an analogue of A/Philippines/2/82) strains were not immunologically significant.

Epidemiology and specific prophylaxis of measles.

In studies in the USSR, a single dose of Leningrad-16 live measles vaccine induced sero-conversion in at least 90% of vaccinees, with a mean titer of serum antibody of 1:32 and high antibody levels throughout the 15 years after vaccination. When the vaccine was correctly stored, transported, and used for mass vaccination, measles-associated morbidity decreased and the circulation of measles virus was interrupted in some towns for several years. However, childhood vaccination over a long period changed the immunologic age of the population and resulted in increased measles-associated morbidity in adults. A program for eradication of measles virus in some areas of the USSR has thus been developed. The ultimate aim of this program is the total eradication of measles. This goal can be achieved only after attainment of a high level of collective immunity (95%) through increased efficacy and quality of the vaccine. The international program of measles eradication should be based on the experiences gained through immunization programs in various countries. The key issues are (1) the elimination of measles epidemics and mortality, (2) the maintenance of a low incidence of measles over a long period, (3) the prevention of measles virus importation through epidemiologic surveillance, and (4) the maintenance of a high level of collective immunity in the total population.

[Antigenic properties of influenza virus type A inactivated by ultraviolet irradiation]. / Antigennye svoistva virusa grippa A, inaktivirovannogo ul'trafioletovym oblucheniem.

The effect of ultraviolet irradiation (UVI) on influenza A virus was studied. UVI of influenza A virus purified by adsorption chromatography on porous glass (PG) was found to result in irreversible inactivation of virus. The rate of inactivation directly depended upon the degree of virus purification. A reduction in the neuraminidase, hemagglutinating and antigenic activity of the virus occurred after a considerably longer UVI (over 7--10 min) than that required for inactivation of the purified virus (1--2 min) with the regimen of inactivation used. No changes in specificity of hemagglutinin and neuraminidase antigens after UVI were observed. The immunogenic activity of hemagglutinin and neuraminidase of the experimental lots of influenza vaccine purified on PG but inactivated by different means (UVI or formalin) was similar.

[Characteristics of the reactogenic and immunogenic properties of killed influence vaccine purified and concentrated by the method of adsorbed chromatography on silicate sorbents]. / Kharakteristika reaktogennykh i immunogennykh svoistv ubitoi grippoznoi vaktsiny, ochishchennoi i kontsentrivoannoi metodom adsorbivovannoi khromatografii na silikatnykh sorbentakh

Reactogenic and immunogenic properties of killed influenza vaccine prepared of various strains of influenza virus by the method of sorption chromatography on sliciate sorbents were studied on small groups of volunteers; there proved to be a moderate reactogenic and a marked immunogenic activity of the experimental batches of the preparation. The dose, the concentration and the method of administration of the vaccine to obtain the immune response were determined. The indices of humoral and local immunity following a single vaccination were studied. On the basis of parenteral immunization of donors with killed influenza vaccine there were obtained experimental samples of the antinfluenza gamma-globulin with an increased specific activity.