[Mutations in the A34R gene increase the immunogenicity of vaccinia virus]. / Мутации в гене A34R, приводящие к увеличению иммуногенности вируса осповакцины.

Vaccination is the most simple and reliable approach of protection to virus infections. The most effective agents are live vaccines, usually low-virulence organisms for humans and closely related to pathogenic viruses or attenuated as a result of mutations/deletions in the genome of pathogenic virus. Smallpox vaccination with live vaccinia virus (VACV) closely related to smallpox virus played a key role in the success of the global smallpox eradication program carried out under the World Health Organization auspices. As a result of the WHO decision as of 1980 to stop smallpox vaccination, humankind has lost immunity not only to smallpox, but also to other zoonotic, orthopoxviruscaused human infections. This new situation allows orthopoxviruses to circulate in the human population and, as a consequence, to alter several established concepts of the ecology and range of sensitive hosts for various orthopoxvirus species. Classic VACV-based live vaccine for vaccination against orthopoxvirus infections is out of the question, because it can cause severe side effects. Therefore, the development of new safe vaccines against orthopoxviral infections of humans and animals is an important problem. VACV attenuation by modern approaches carried out by targeted inactivation of certain virus genes and usually leads to a decrease in the effectiveness of VACV in vivo propagation. As a result, it can cause a diminishing of the immune response after administration of attenuated virus to patients at standard doses. The gene for thymidine kinase is frequently used for insertion/inactivation of foreign genes and it causes virus attenuation. In this research, the effect of the introduction of two point mutations into the A34R gene of attenuated strain LIVP-GFP (ТК-), which increase the yield of extracellular enveloped virions (EEV), on the pathogenicity and immunogenicity of VACV LIVP-GFP-A34R administered intranasally to laboratory mice were studied. It was shown that increase in EEV production by recombinant strain VACV LIVP-GFP-A34R does not change the attenuated phenotype characteristic of the parental strain LIVP-GFP, but causes a significantly larger production of VACV-specific antibodies.

[Development of the drug oncolytic immunotherapy based on vaccinia viruses (Vaccinia virus, Orthopoxvirus, Chordopoxvirinae, Poxviridae) against breast cancer.]

INTRODUCTION: Currently, new directions in cancer therapy are actively developing, one of which is oncolytic immunotherapy. This approach would be to use of viruses as cancer specific cytolytic agents capable of stimulating both the tumor-specific and non-specific immune response. The objective paper was obtain a recombinant vaccinia virus containing genes encoding immunostimulating molecules and study oncolytic and immunostimulating properties of recombinant virus. MATERIAL AND METHODS: MTT test, ELISA, methods of transient dominant selection. RESULTS: The recombinant vaccinia virus (L-IVP_oncoB) were obtained with deletion of the gene encoding thymidine kinase and had an integrated gene encoding GM-CSF. Also the virus have deletion of the gene encoding viral growth factor and integrated genes encoding synthetic tumor-specific polyepitopic immunogens. It was shown that the modifications made to the viral genome did not affect the growth characteristics of the virus when cultured on CV-1 and 4647 cell cultures, and the cytopathogenic efficacy of the virus was determined in relation to cancer cultures of cells of various genesis. In in vivo experiment, it was revealed that the polyepitopic construct in the genome L-IVP_oncoB is able to initiate a change in the profile of cytokines. DISCUSSION: The obtained data characterized L-IVP_oncoB as a promising cytopathogenic and immunostimulating agent and showed the need for further study of its properties as means of oncolytic immunotherapy. CONCLUSION: The basic experiments on the evaluation of the biological properties of the obtained L-IVP_oncoB, which are necessary for the characterization of the oncolytic virus, have been carried out.

The Influence of an Elevated Production of Extracellular Enveloped Virions of the Vaccinia Virus on Its Properties in Infected Mice.

The modern approach to developing attenuated smallpox vaccines usually consists in targeted inactivation of vaccinia virus (VACV) virulence genes. In this work, we studied how an elevated production of extracellular enveloped virions (EEVs) and the route of mouse infection can influence the virulence and immunogenicity of VACV. The research subject was the LIVP strain, which is used in Russia for smallpox vaccination. Two point mutations causing an elevated production of EEVs compared with the parental LIVP strain were inserted into the sequence of the VACV A34R gene. The created mutant LIVP-A34R strain showed lower neurovirulence in an intracerebral injection test and elevated antibody production in the intradermal injection method. This VACV variant can be a promising platform for developing an attenuated, highly immunogenic vaccine against smallpox and other orthopoxvirus infections. It can also be used as a vector for designing live-attenuated recombinant polyvalent vaccines against various infectious diseases.