Immunization with influenza A NP-expressing vaccinia virus recombinant protects mice against experimental infection with human and avian influenza viruses.

Two-fold immunization of Balb/c mice with a vaccinia virus recombinant expressing the NP protein of influenza A/PR8/34 (H1N1) virus under the control of a strong synthetic promoter induced specific antibodies and protected animals against low-dose challenge by mouse-adapted heterosubtypic variants of human A/Aichi2/68 (H3N2) and avian A/Mallard/Pennsylvania/10218/84 (H5N2) influenza virus strains. The surviving immunized animals had lower anti-hemagglutinin antibody titers compared to non-immunized mice. There was no difference in viral titers in lungs of immunized and non-immunized animals that succumbed to the infection.

Combined prime-boost vaccination against tick-borne encephalitis (TBE) using a recombinant vaccinia virus and a bacterial plasmid both expressing TBE virus non-structural NS1 protein.

Background: Heterologous prime-boost immunization protocols using different gene expression systems have proven to be successful tools in protecting against various diseases in experimental animal models. The main reason for using this approach is to exploit the ability of expression cassettes to prime or boost the immune system in different ways during vaccination procedures. The purpose of the project was to study the ability of recombinant vaccinia virus (VV) and bacterial plasmid, both carrying the NS1 gene from tick-borne encephalitis (TBE) virus under the control of different promoters, to protect mice against lethal challenge using a heterologous prime-boost vaccination protocol.

[Interaction between the human and simian adenoviruses in human cells: complementation, transcapsidation and formation of defective adeno-adeno hybrids].

It was for the first time that complementation between the human and simian adenoviruses in human cells as well as the ability of the human adenovirus Ad2 (HADv2) genome to transform completely into the simian adenovirus SA7(C8) (SADv15) capsid (transcapsidation) was demonstrated. A defective adeno-adeno hybrid (recombinant) between the above viruses is described; the recombinant has the SA7(C8) capsid and Ad2 genome with a 10% insertion of SA7(C8) in the central region. Defective hybrid virions are able to replicate both in human and simian cells by using the SA7(C8) virus as helper.

Vaccinia virus recombinant expressing gene of tick-borne encephalitis virus non-structural NS1 protein elicits protective activity in mice.

A vaccinia virus recombinant containing the non-structural tick-borne encephalitis virus (TBEV) NS1 gene was developed. The recombinant expressed native dimeric form of the NS1 protein in infected cells and protected mice against lethal infection with TBEV.

[Hybrids of human and monkey adenoviruses (adeno-adeno hybrids) that can reproduce in monkey cells: biological and molecular genetic peculiarities].

A highly oncogenic monkey adenovirus SA7(C8) facilitates the reproduction of human adenovirus type 2 (Ad2) in monkey cells. Upon mixed infection of monkey cells with both viruses, these viruses recombine producing defective adeno-adeno hybrids Ad2C8 serologically identical to Ad2 and capable of assisting Ad2 to reproduce in monkey cells. Ad2C8 and Ad2 form an intercomplementary pair inseparable in monkey cells.

Hepatitis B virus proteins expressed by recombinant vaccinia viruses: influence of preS2 sequence on expression surface and nucleocapsid proteins in human diploid cells.

Fifteen vaccinia virus (VV) recombinants derived from VV strains Praha, LIVP and DD (i.e. Dryvax Wyeth vaccine-derived) and expressing genes for S, preS2-S or c antigens of hepatitis B virus (HBV) were tested in monkey CV-1 cells and human diploid LEP cells.

Immunogenicity of recombinant vaccinia viruses expressing hepatitis B virus surface antigen in mice.

The ability of different recombinant vaccinia viruses (RVV) expressing hepatitis B virus surface antigen (HBsAg) to induce anti-HBs and anti-vaccinia virus responses has been analyzed in mice. The RVVs tested differed with regard to the original vaccinia virus strain used as vector and the site of insertion of a foreign gene. It was found that the immunological responses to RVVs based on the WR strain were higher than those to RVVs based on the Lister strain.

Two vaccinia virus recombinants expressing HBsAg with different concentration of A- and pre-S2 antigenic determinants.

Comparative studies of two vaccinia virus (VV) recombinants expressing the hepatitis B virus (HBV) surface antigen (HBsAg) including the pre-S2 region (M-protein) showed that the L-pre-S2/15 recombinant expressed 5-fold more HBsAg as determined by the content of a-determinant than the recombinant v137. However, both recombinants expressed comparable amounts of the pre-S2 antigenic determinant as assessed by enzyme immunoassay with monoclonal antibodies. According to our calculations, one HBsAg unit expressed by the recombinant v137 contained 7-9 times more pre-S2 antigen than did one HBsAg unit expressed by the L-pre-S2/15 recombinant.