Vaccinia virus (VACV) is an enveloped DNA virus from the Orthopoxvirus family, various strains of which were used in the successful eradication campaign against smallpox. Both original and newer VACV-based replicating vaccines reveal a risk of serious complications in atopic individuals. VACV encodes various factors interfering with host immune responses at multiple levels. In atopic skin, the production of type I interferon is compromised, while VACV specifically inhibits the phosphorylation of the Interferon Regulatory Factor 3 (IRF-3) and expression of interferons. To overcome this block, we generated a recombinant VACV-expressing murine IRF-3 (WR-IRF3) and characterized its effects on virus growth, cytokine expression and apoptosis in tissue cultures and in spontaneously atopic Nc/Nga and control Balb/c mice. Further, we explored the induction of protective immune responses against a lethal dose of wild-type WR, the surrogate of smallpox. We demonstrate that the overexpression of IRF-3 by WR-IRF3 increases the expression of type I interferon, modulates the expression of several cytokines and induces superior protective immune responses against a lethal poxvirus challenge in both Nc/Nga and Balb/c mice. Additionally, the results may be informative for design of other virus-based vaccines or for therapy of different viral infections.

• Keywords
• IRF-3, Nc/Nga mice, atopic dermatitis, cytokines, eczema vaccinatum, immunization, interferon beta, interleukin-1 beta, smallpox, vaccinia virus,
• MeSH
• Gene Expression genetics   MeSH
• Immunity immunology   MeSH
• Poxviridae Infections immunology   prevention & control   MeSH
• Interferon Type I metabolism   MeSH
• Interferon Regulatory Factor-3 genetics   immunology   MeSH
• Interleukin-1beta immunology   MeSH
• Skin immunology   MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• Poxviridae pathogenicity   MeSH
• Gene Expression Regulation, Viral genetics   MeSH
• Virus Replication immunology   MeSH
• Vaccinia virology   MeSH
• Viral Vaccines immunology   MeSH
• Vaccinia virus genetics   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Interferon Type I MeSH
• Interferon Regulatory Factor-3 MeSH
• Interleukin-1beta MeSH
• Viral Vaccines MeSH

Smallpox vaccine based on live, replicating vaccinia virus (VACV) is associated with several potentially serious and deadly complications. Consequently, a new generation of vaccine based on non-replicating Modified vaccinia virus Ankara (MVA) has been under clinical development. MVA seems to induce good immune responses in blood tests, but it is impossible to test its efficacy in vivo in human. One of the serious complications of the replicating vaccine is eczema vaccinatum (EV) occurring in individuals with atopic dermatitis (AD), thus excluding them from all preventive vaccination schemes. In this study, we first characterized and compared development of eczema vaccinatum in different mouse strains. Nc/Nga, Balb/c and C57Bl/6J mice were epicutaneously sensitized with ovalbumin (OVA) or saline control to induce signs of atopic dermatitis and subsequently trans-dermally (t.d.) immunized with VACV strain Western Reserve (WR). Large primary lesions occurred in both mock- and OVA-sensitized Nc/Nga mice, while they remained small in Balb/c and C57Bl/6J mice. Satellite lesions developed in both mock- and OVA-sensitized Nc/Nga and in OVA-sensitized Balb/c mice with the rate 40-50%. Presence of mastocytes and eosinophils was the highest in Nc/Nga mice. Consequently, we have chosen Nc/Nga mice as a model of AD/EV and tested efficacy of MVA and Dryvax vaccinations against a lethal intra-nasal (i.n.) challenge with WR, the surrogate of smallpox. Inoculation of MVA intra-muscularly (i.m.) or t.d. resulted in no lesions, while inoculation of Dryvax t.d. yielded large primary and many satellite lesions similar to WR. Eighty three and 92% of mice vaccinated with a single dose of MVA i.m. or t.d., respectively, survived a lethal i.n. challenge with WR without any serious illness, while all Dryvax-vaccinated animals survived. This is the first formal prove of protective immunity against a lethal poxvirus challenge induced by vaccination with MVA in an atopic organism.

• MeSH
• Dermatitis, Atopic immunology   pathology   MeSH
• Immunization MeSH
• Immunoglobulin E blood   immunology   MeSH
• Immunoglobulin G blood   immunology   MeSH
• Poxviridae Infections immunology   mortality   prevention & control   MeSH
• Kaposi Varicelliform Eruption etiology   pathology   MeSH
• Skin pathology   MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Antibodies, Neutralizing blood   immunology   MeSH
• Antibodies, Viral blood   immunology   MeSH
• Smallpox Vaccine immunology   MeSH
• Vaccinia virus genetics   immunology   MeSH
• Animals MeSH
• Check Tag
• Male MeSH
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Immunoglobulin E MeSH
• Immunoglobulin G MeSH
• Antibodies, Neutralizing MeSH
• Antibodies, Viral MeSH
• Smallpox Vaccine MeSH

Smallpox was declared eradicated in 1980. However recently, the need of agents effective against poxvirus infection has emerged again. In this paper, we report an original finding that two redox-modulating agents, the ethacrynic and alpha-lipoic acids (EA, LA), inhibit growth of vaccinia virus (VACV) in vitro. The effect of EA and LA was compared with those of beta-mercaptoethanol, DTT and ascorbic acid, but these agents increased VACV growth in HeLa G cells. The inhibitory effects of EA and LA on the growth of VACV were further confirmed in several cell lines of different embryonic origin, in epithelial cells, fibroblasts, macrophages and T-lymphocytes. Finally, we have analyzed the mechanism of action of the two agents. They both decreased expression of VACV late genes, as demonstrated by western blot analysis and activity of luciferase expressed under control of different VACV promoters. In contrast, they did not inhibit virus entry into the cell, expression of VACV early genes or VACV DNA synthesis. The results suggest new directions in development of drugs effective against poxvirus infection.

• MeSH
• Antiviral Agents pharmacology   MeSH
• Gene Expression drug effects   MeSH
• HeLa Cells MeSH
• Cells, Cultured MeSH
• Ethacrynic Acid pharmacology   MeSH
• Thioctic Acid pharmacology   MeSH
• Humans MeSH
• Luciferases metabolism   MeSH
• Viral Plaque Assay MeSH
• Virus Replication drug effects   MeSH
• Genes, Reporter MeSH
• Vaccinia virus drug effects   growth & development   MeSH
• Blotting, Western MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Antiviral Agents MeSH
• Ethacrynic Acid MeSH
• Thioctic Acid MeSH
• Luciferases MeSH