[The phenotypic characteristics of healthy carriers of the antigenic structures of the influenza A virus]. / Fenotipicheskie osobennosti zdorovykh nositelei antigennykh struktur virusa grippa A.

Highly sensitive methods for the detection of viral antigens with the use of monoclonal or polyclonal enzyme immunoassay test systems, as well as virus-specific nucleic sequences (NS-gene) in polymerase chain reaction, made it possible to establish the fact of long-term asymptomatic virus carriership (AVC) in some of adolescent schoolchildren in a closed group. The occurrence of AVC varied at different phases of the epidemic process. The tendency to AVC was observed in individuals having blood group B (III) and HLA-A9 antigen of the major histocompatibility complex. The development of AVC occurred in the presence of a decreased level of humoral immunity. AVC was mainly registered among individuals, relatively resistant to relapsing clinically pronounced forms of respiratory virus infections.

[Elaboration of the polymerase chain reaction system for subtype specific differentiation of influenza A virus strains]. / Razrabotka sistemy polimeraznoi tsepnoi reaktsii dlia subtipospetsifichnoi differentsiatsii shtammov virusa grippa A.

New subtype specific primers for hemagglutinin (H1, H2, H3) of influenza A viruses were selected. The specificity of the primers' performance was tested in a model experiment which used cDNA synthesized on the vRNA from the collection of influenza A viruses (H1, H2, H3 subtypes) as templates. The sensibility of the PCR system was determined on DNA plasmids- and RNA templates (with preliminary reverse transcription) and amounted to 10(2) and 10(5)-10(6) virion particles, respectively.

[Genetic predisposition to latent influenza A virus in children with blood type B(III) as a possible cause of new epidemiologic strains in the countries of South-Eastern Asia]. / Geneticheskaia predraspolozhennost detei s gruppoi krovi B(III) k latentnomu nositelstvu virusov grippa A - vozmozhnaia prichina vozniknoveniia novykh épidemicheskikh shtammov v stranakh Iugo- Vostochnoi Azii.

Regular clinical and epidemiological surveys of two groups of healthy 14-16-year-old boys were carried out for 3 years from September 1989 to May 1992 to investigate the latent circulation of influenza A viruses in the human population. Once or twice a quarter clinical materials were laboratorily studied to detect virus antigens, virus-specific NA-sequences and to determine changes in humoral immunity. The latent circulation of influenza A viruses might be identified in 10-20% of cases long before (2-4 months) the onset of epidemic development. The incidence of epidemic isolations was found to reach 33-36%, gradually decreasing from 29 to 9 or 3.5% in the postepidemic period. The long-term persistence (for 5 months) of virus antigens was reported among healthy children who had chiefly blood group B(III). The new hypothesis that the genetic predisposition of children with blood group B(III) to latent persistence of influenza A viruses may be a possible cause of the emergence of new epidemic strains in the South-East Asian countries has been forwarded.

[Induction of mutations in Streptomyces antibioticus]. / Induktsiia mutatsii u Streptomyces antibioticus.

Mutagenic action of UV-light, nitrosoguanidine and nitrosomethylbiuret was studied in Streptomyces antibioticus VNIIA 1607. Nitrosomethylbiuret appeared to be most effective inducer of auxotrophic mutations (mutation frequency reached 15%). By means of hybridological analysis, it was shown that heterokaryons predominated in the progeny of mixed cultures of multiply marked strains. The test for functional allelism using heterokaryons permitted us to divide 93 independently obtained mutations into 28 complementation groups.