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Trials of the first Soviet live recombinant smallpox-hepatitis B vaccine (SHBV) in volunteers (20 men aged 18-20 years) showed its safety, good "take"-rate, and lower reactogenicity as compared with the standard smallpox vaccine (LIVP strain). Smallpox virus-neutralizing antibodies in response to SHBV were produced as well as in response to the smallpox vaccine. Revaccination of human subjects with smallpox vaccine and SHBV 45 days after the previous vaccination resulted in antibody booster to vaccinia virus. After two inoculations of SHBV at an interval of 45 days no anti-HBsAg antibodies were found for 3 months after the last vaccination. However, even a single vaccination with SHBV induced priming to HBsAg. This could be demonstrated after inoculation of the subjects vaccinated with SHBV with one dose of plasma hepatitis vaccine. In the subjects vaccinated with SHBV antibody in response to the plasma vaccine formed more frequently and in higher titres than in those prevaccinated with smallpox vaccine or placebo.

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The immune blotting method using monoclonal antibodies to Ml protein showed protein Ml to migrate in several bands in polyacrylamide gel electrophoresis (PGE) of influenza A virus polypeptides. The heterogeneous distribution of Ml protein in PGE is due to the formation of aggregates: dimers, trimers, and polymers of a higher order. The capacity of Ml protein for aggregation is typical not of all influenza virus strains and most likely is not associated with gel overloading. Since dimers and trimers of Ml protein comigrate in the gel with virus-specific proteins such as NP and proteins of a polymerase complex, this circumstance should be take into consideration in using PGE for isolation of pure influenza virus proteins.

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Immune blotting analysis was used to study antibody production to virion proteins of vaccinia virus (VV) in response to inoculation of human volunteers and rabbits with VV (LIVP strain) and its genetic engineering recombinant variants carrying a gene of hepatitis B virus surface antigen (LIOGEN-HB/C2-TK-) and, plus to that, the TK gene of herpes simplex virus (LIOGEN-HB/C2-TK+). In the blood of human subjects vaccinated 10-15 years earlier antibodies to many virion proteins were demonstrated: not only to surface 42K, 35K, 11K, but also to nucleoid proteins 135K, 88K, 62K, 60K, 26K. Vaccination with genetic engineering viruses results in stimulation of synthesis of antibodies to VV virion proteins. No differences in the antigenic properties of recombinant viruses were found. The results obtained in model experiments in rabbits verified those obtained in human volunteers.

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It has been shown by immunoblotting that antibodies to HSV-1 nucleocapsid proteins (39-45K) predominate at the early stages of infection (up to day 21 after infection) in rabbits. At later stages (up to day 75) the intensity of bands corresponding to virus-specific glycoproteins (presumably gD, gE, gC) increases. At the same time the level of antibodies to nucleocapsid proteins diminishes. In ELISA the same pattern was obtained using envelope and nucleo-capsid proteins denatured by SDS and 2-mercaptoethanol. The possibility of using individual HSV antigens for the development of highly specific diagnostic ELISA test-systems is discussed.

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A stable chronically rubella virus-infected culture of HEp-2-BK cells existing for over 30 months has been obtained as a result of a single inoculation and further passages. This system is characterized by the lack of cell destruction and permanent production of infectious virus in titres of 2.5-6.3 lg PFU/ml. Synthesis of RNAs of the same classes as in the acute infection was demonstrated in the chronically infected cell culture (CICC) but virion RNA production was less marked. Only a portion of the cells in the population was found to carry the infectious virus. Virus-free cell clones were as susceptible to rubella virus as the control culture. The process of persistence proved to be resistant to virus-specific antibody as well as to the effect of higher (40 degree C) or lower (34 degree C) temperatures. Actinomycin D, 5-bromodeoxyuridine, and 5-iodo-2-deoxyuridine exerted no significant effect on virus reproduction in CICC which, combined with negative results of the experiments on transfection of the susceptible cultures with DNA preparations recovered from CICC, evidenced against the role of integration mechanisms in the establishment and maintenance of the HEp-2-BK system. A clear-cut interference with a heterologous virus was demonstrated in HEp-2-BK culture. The formation of the chronic form of infection in HEp-2-BK culture appears to be due to weak cytocidal properties of rubella virus and formation of endogenous interferon.

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Virus particles produced in acute and chronic infection of cell cultures with tick-borne encephalitis virus (TBE) and examined by centrifugation in sucrose density gradient had the buoyant density of 1.19 g/ml and sedimentation constant 290 S. Studies of the synthesis of virus-specific RNAs in the cytoplasm of TBE virus chronically infected cells revealed synthesis of all RNA classes typical of TBE virus reproduction in acutely infected cells. The difference was in the high percentage of polyadenylation of intracellular virion RNA in chronic infection (30%) as compared with polyadenylation of virion RNA in acute infection (8%). This fact may be one of the causes of a low infectious virus yield in chronically infected cultures where the level of virus-specific antigen synthesis is high.

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Deoxyribonucleoprotamine (DNPn) from sonicated nuclei of sturgeon sperm heads was studied by means of ring dichroism. A derivative analysis of DNA and DNPn melting curves in 1 mM Tris. HCl pH 8.0 revealed the fraction of protein-free DNA being about 30% and suggested the preferable binding of protamine molecules with AT-rich DNA regions. The latter is also confirmed by the data on ring dichroism of protein-poor soluble DNAPn fraction in 0,14 M NaCl. Ring dichroism of DNA and DNPn in 1 mM Tris coinsides at the wavelength of 310-240 nm at concentrations of 500-50 mkg/ml. Dilution of DNPn to 5 mkg-ml resulted in the decrease of the ellipticity at 275 nm and produced no effect at 260-210 nm. The effect observed is suggested to be due to a partial transition of DNA in DNPn into C-form under the dilution as a result of a higher molecule hydration and a destruction of some hydrogen bonds between guanidine residues of arginine and oxygen of phosphate groups, stabilyzing DNA in the B-form. Ring dichroism spectrum of protamine, calculated by the subtraction of DNA spectrum from DNPn spectrum at the region of 240-210 nm coinsides with that of free protamine and indicates the absence of an ordered structure in protamine molecules in DNPn.

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