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CV-1 cells were preinfected with H7-SV40 recombinant vector and superinfected with influenza viruses A/USSR/90/77 (H1N1), A/Duck/Czechoslovakia/56 (H4N6), or B/Hongkong/73. A fraction of the yields of influenza A viruses was infectious without trypsin treatment due to the incorporation of cleaved H7 hemagglutinin into virions. The specificity of the effect was confirmed by neutralization of the infectivity with anti-H7 serum. At a low multiplicity of infection the incorporation of H7 hemagglutinin into virions allowed the virus to replicate without trypsin in a multi-cycle manner. The fraction of the infectious virus and the kinetics of the multi-cycle infection in H7-expressing cells were similar in the cells superinfected with A/USSR/90/77 and with A/Duck/Czechoslovakia/56 viruses, thus demonstrating a low specificity of interaction between H7 hemagglutinin and heterologous M2 proteins. The superinfection of H7-expressing cells with influenza B/Hongkong/73 virus did not produce infectious phenotypically mixed virus, which may be regarded as an indication of inability of influenza B virus NB protein to replace functionally the influenza A virus M2 protein in its interaction with hemagglutinin.

The plasmid pH5KV14 containing the right end of the Ad5 viral genome (45-100 map units) with deleted nonessential E3 region (78.5-84 map units) has been constructed. A helper-independent recombinant virus Ad5KV14 has been obtained as a result of in vivo transformation of the line 293 human cells by the pH5KV14 plasmid DNA and an EcoRI-A DNA fragment of the virus Ad5 and subsequent recombination. A nondefective recombinant virus Ad5KV17 containing the Ad5 genome with the E3 region substituted for the plasmid DNA fragment coding for the kanamycin-resistance has been constructed by a similar procedure.

The transforming and oncogenous activity of uncleaved DNA of simian adenovirus SA7 (AdSA7) and the products of its restriction by endonucleases R. Bam HI and R. SalI was studied. It was shown that uncleaved virus DNA transformed the rat kidney cells and rat embryo fibroblasts and induced tumors in newborn hamsters. AdSA7 DNA, hydrolysed by R. Bam HI, posessed the transforming activity. The mixture of DNA fragments, obtained after hydrolysis by R. SalI was oncogenous in hamsters.

A total preparation of cytoplasmic RNA was isolated from late stage-infected African green monkey kidney cells using phenol extraction procedure. The poly (A)-containing mRNA fraction was selected on oligo(dT)-cellulose columns. The resulting mRNA preparations were heterogenous in size and contained about 20--60% of SA7-derived sequences. SA7 late mRNA was efficiently translated in rabbit reticulocyte cell-free system giving rise to a number of polypeptide products that were related by antigenicity to authentic SA7 virion proteins. The main translation product having a molecular weight of 114 kilodaltons was identified as intact SA7 hexon protein.

The data on the transforming activity of intact DNA of human adenovirus type 6 and that fragmented by restrictases Bam H I (31.3% of the genome), Bgl 2 (9.3% of the genome), and Hind 3 (7.6% of the genome) in a primary culture of rat kidney cells are presented. The activity of the specimens varied within 1.1-2.1 foci per 1 microgram of DNA. From the transformation foci 5 cell lines were derived and their properties (T-antigen production, integration of adenovirus genome, phenotypic features) were studied.

Methods for generation of cell lines transformed by highly oncogenic simian adenovirus SA7, nononcogenic human adenovirus type 6 and their DNAs are described. WAG rat kidney cells were used for transformation. To produce 1 focus of transformation, 1.7 X 10(6) PFU of SA7 virus is required. Intact and fragmented DNA of both viruses may be quite effectively used for transformation. For production of 1 transformation focus 1.2 microgram SA7 DNA and 1.1 microgram type 6 adenovirus DNA is required. In most cases, DNA fragmentation increases the transforming activity which has been shown to be associated with the left genome region of both viruses under study.

Respiratory syncytial virus multiplying activity in the lungs of newborn and 6-day-old cotton rats, induced production of considerable amounts of interferon. Interferon production correlated with virus multiplication. Lower interferon titers were observed in the lungs of newborn cotton rats than in the lungs of 6-day-old animals. RS virus also induced production of serum interferon upon intraperitoneal inoculation, its titers being 2 times as low as after inoculation of equal doses of Newcastle disease virus. Poly I: poly C was shown to be a quite active interferon inducer in cotton rats and to inhibit RS virus reproduction in their lungs.

Liposomes connected with influenza viral glycoproteins increase by 1-2 orders the specific infectiousness of DNA from SV-40 or monkey adenovirus SA7 as compared with the one registered when the standard method of calcium precipitation is used.