[Effect of HBc-antigen expression on replication of recombinant Salmonella strains in vivo and in vitro].

The development of therapeutic vaccines against chronic hepatitis B is a major challenge facing modern medicine. HBc antigen-expressing DNA-vaccines designed to be transported into the organism by attenuated Salmonella appear to be good candidates for the purpose. Expression of HBc-antigen was earlier shown to lead to the loss of ability of attenuated Salmonella bearing the DNA-vaccine to multiply in the host lymphoid tissue of mice after per rectum immunization and in human monocyte culture. The aim of the study was to assess the influence of HBc-antigen expression on replication of a virulent strain of wild-type Salmonella serotype Enteritidis in the murine lymphoid tissue after per rectum infection and in human blood monocytes. HBc expression was shown to inhibit propagation of Salmonella in both model systems despite its high virulence.

[Persistence of the Salmonella enteritidis recombinant strain with expressed HBc antigen in mice and macrophage culture].

The behavior of S. enteritidis recombinant strain E-23/pKDNA(3.1) with HBc antigen expressed by the eukaryotic promoter (DNA vaccine) in the body of mice after their infection per rectum and in the culture of macrophages was studied. The expression of HBc was shown to lead to the loss of the capacity of salmonellae for persistence in parenteral lymphoid tissue and for inducing the formation of anti-HBc antibodies. The study of the interaction of salmonellae with the macrophage culture revealed that the synthesis of HBc antigen inhibited the intracellular multiplication of salmonellae.

[Hepatitis B vaccine improvement].

Data about ongoing researches in order to increase efficacy and immunogenicity of licensed hepatitis B vaccines and to develop new therapeutic vaccines for chronic hepatitis B treatment are reviewed.

[The possibility of using the attenuated recombinant strain of Salmonella enteritidis producing the HBc-antigen as a rectal vaccine in an experiment]. / Vozmozhnost' ispol'zovaniia attenuirovannogo rekombinantnogo shtamma Salmonella enteritidis, produtsiruiushchego HBc-antigen, v kachestve vaktsiny rektal'nogo primeneniia v eksperimente.

Designing of a therapeutic vaccine for patients with chronic hepatitis B is a task of contemporary medicine. The natural way of administering the vaccine is the most attractive and inexpensive immunization variant. The use of attenuated strain Salmonella as a carrier of the virus antigen fits the purpose. With this idea in mind, the potentialities of the recombinant attenuated strain Salmonella Enteritidis E-23/pKHBc to replicate in the intestine, mesenteric nods and spleen of mice and to stimulate the immune response to HBc-antigen after its rectal administration (as suppositories) in mice were investigated. It was shown that the recombinant strain is discharged from the intestine within 6 hours after immunization, whereas, it is discharged on day 2 after immunization from the lymphatic nods and is traced there during the 5 subsequent days. Besides, the recombinant strain also possessed the possibility to persist in the spleen of mice for 42 days and to induce there the formation of antibodies to HBc-antigen.

[Some approaches to elaborating vaccines against the HIV infection]. / Nekotorye podkhody k razrabotke vaktsiny protiv VICH-infektsii.

A variety of approaches to creating vaccines against the HIV-infection are discussed in the paper. It is demonstrated that vaccines can be used both for treatment and prevention. They can be synthetic, DNA-vaccines and vector-type ones based on the attenuated recombinant strain of Salmonella. Apart from gp120, reverse transcriptase and tat-gene products can be used as the antigen.