Viral host-range factor C7 or K1 is essential for modified vaccinia virus Ankara late gene expression in human and murine cells, irrespective of their capacity to inhibit protein kinase R-mediated phosphorylation of eukaryotic translation initiation factor 2alpha.

Vaccinia virus (VACV) infection induces phosphorylation of eukaryotic translation initiation factor 2alpha (eIF2alpha), which inhibits cellular and viral protein synthesis. In turn, VACV has evolved the capacity to antagonize this antiviral response by expressing the viral host-range proteins K3 and E3. This study revealed that the host-range genes K1L and C7L also prevent eIF2alpha phosphorylation in modified VACV Ankara (MVA) infection of several human and murine cell lines.

The orthopoxvirus 68-kilodalton ankyrin-like protein is essential for DNA replication and complete gene expression of modified vaccinia virus Ankara in nonpermissive human and murine cells.

Modified vaccinia virus Ankara (MVA) is a highly attenuated and replication-deficient vaccinia virus (VACV) that is being evaluated as replacement smallpox vaccine and candidate viral vector. MVA lacks many genes associated with virulence and/or regulation of virus tropism. The 68-kDa ankyrin-like protein (68k-ank) is the only ankyrin repeat-containing protein that is encoded by the MVA genome and is highly conserved throughout the Orthopoxvirus genus.

Marker gene swapping facilitates recombinant Modified Vaccinia Virus Ankara production by host-range selection.

Modified Vaccinia Virus Ankara (MVA) is employed widely as an experimental and human vaccine vector for its lack of replication in mammalian cells and high expression of heterologous genes. Recombinant MVA technology can be improved greatly by combining transient host-range selection (based on the restoration in MVA of the deleted vaccinia gene K1L) with the differential expression of fluorescent proteins. Recombinant virus results from swapping a red protein gene (in the acceptor virus) with a cassette of the transfer plasmid comprising the transgene and the green marker K1Lgfp (a chimeric gene comprising K1L and EGFP).

Vaccination with a Modified Vaccinia Virus Ankara-based vaccine protects mice from allergic sensitization.

Background: Currently, no treatment is available for food allergy and strict avoidance of the allergenic food remains the only way to manage the allergy. New strategies leading to a safe and efficacious food allergy treatment are required. Modified vaccinia virus Ankara (MVA), which allows high levels of expression of recombinant protein in vivo and gives rise to a Th1-biased specific immune response, was used as a prophylactic vaccine in a murine model of ovalbumin (OVA) allergy.

A prime-boost vaccination protocol optimizes immune responses against the nucleocapsid protein of the SARS coronavirus.

Severe acute respiratory syndrome (SARS) is a serious infectious disease caused by the SARS coronavirus. We assessed the potential of prime-boost vaccination protocols based on the nucleocapsid (NC) protein co-administered with a derivative of the mucosal adjuvant MALP-2 or expressed by modified Vaccinia virus Ankara (MVA-NC) to stimulate humoral and cellular immune responses at systemic and mucosal levels. The obtained results demonstrated that strong immune responses can be elicited both at systemic and mucosal levels following a heterologous prime-boost vaccination protocol consisting in priming with NC protein add-mixed with MALP-2 by intranasal route and boosting with MVA-NC by intramuscular route.

In vivo attenuation of recombinant murine gammaherpesvirus 68 (MHV-68) is due to the expression and immunogenicity but not to the insertion of foreign sequences.

Recombinant herpesviruses are increasingly utilized to study herpesvirus biology. For recombinant viruses carrying insertions of foreign sequences, attenuated phenotypes in vivo have been frequently observed. In most cases, the underlying mechanisms were not clear or have not been investigated.

The human spleen is a major reservoir for long-lived vaccinia virus-specific memory B cells.

The fact that you can vaccinate a child at 5 years of age and find lymphoid B cells and antibodies specific for this vaccination 70 years later remains an immunologic enigma. It has never been determined how these long-lived memory B cells are maintained and whether they are protected by storage in a special niche. We report that, whereas blood and spleen compartments present similar frequencies of IgG(+) cells, antismallpox memory B cells are specifically enriched in the spleen where they account for 0.

Protective vaccination with hepatitis C virus NS3 but not core antigen in a novel mouse challenge model.

Background: Efficient vaccines against hepatitis C virus (HCV) infection are urgently needed. Vaccine development has been hampered by the lack of suitable small animal models to reliably test the protective capacity of immmunization.

Methods: We used recombinant murine gammaherpesvirus 68 (MHV-68) as a novel challenge virus in mice and tested the efficacy of heterologous candidate human vaccines based on modified vaccinia virus Ankara or adenovirus, both delivering HCV non-structural NS3 or core proteins.

Evaluation of modified vaccinia virus Ankara as an alternative vaccine against smallpox in chronically HIV type 1-infected individuals undergoing HAART.

The fear of malevolent use of variola virus by terrorists has led to the implementation of a health care worker vaccination program and to the consideration of vaccination for the general public. However, due to concerns about side effects of the classical smallpox vaccine, especially for immunocompromised individuals, a safer vaccine is urgently needed. We characterized the immunogenicity of modified vaccinia virus Ankara (MVA), one of the more promising alternative smallpox vaccines, in a cohort of 10 chronically HIV-1-infected individuals undergoing highly active antiretroviral therapy (HAART).

Recombinant murine gammaherpesvirus 68 (MHV-68) as challenge virus to test efficacy of vaccination against chronic virus infections in the mouse model.

Efficient vaccines against AIDS, Hepatitis C and other persistent virus infections are urgently needed. Vaccine development has been especially hampered by the lack of suitable small animal models to reliably test the protective capacity of candidate vaccines against such chronic viral infections. A natural mouse pathogen such as MHV-68 that persists lifelong after infection, appears to be a particularly promising candidate for a more relevant model system.

Vaccine-induced early control of hepatitis C virus infection in chimpanzees fails to impact on hepatic PD-1 and chronicity.

Unlabelled: Broad T cell and B cell responses to multiple HCV antigens are observed early in individuals who control or clear HCV infection. The prevailing hypothesis has been that similar immune responses induced by prophylactic immunization would reduce acute virus replication and protect exposed individuals from chronic infection. Here, we demonstrate that immunization of naïve chimpanzees with a multicomponent HCV vaccine induced robust HCV-specific immune responses, and that all vaccinees exposed to heterologous chimpanzee-adapted HCV 1b J4 significantly reduced viral RNA in serum by 84%, and in liver by 99% as compared to controls (P=0.

Short-term, but not post-exposure, protection against lethal orthopoxvirus challenge after immunization with modified vaccinia virus Ankara.

Safety-tested vaccinia virus (VACV) MVA serves as a candidate third-generation vaccine against smallpox. Here, MVA immunization of mice shortly before or after lethal respiratory challenge with VACV Western Reserve was investigated. Whilst post-exposure treatment failed to protect animals, immunizations on day 2 prior to challenge were fully protective.

Inactivation of the viral interleukin 1beta receptor improves CD8+ T-cell memory responses elicited upon immunization with modified vaccinia virus Ankara.

Interleukin 1 (IL1) is an important regulator of inflammatory responses and contributes to host immune defence against infection. Vaccinia virus encodes a viral soluble IL1beta receptor (IL1betaR), which modulates the acute-phase host response to infection and might influence the induction of immune responses against virus-associated antigens. Here, modified vaccinia virus Ankara (MVA) mutants defective in IL1betaR production were produced by insertion of selectable marker gene sequences that precisely deleted the IL1betaR coding sequences from the MVA genome (MVA-DeltaIL1betaR).

Protective CD8 T cell immunity triggered by CpG-protein conjugates competes with the efficacy of live vaccines.

In contrast to infectious (live) vaccines are those based on subunit Ag that are notoriously poor in eliciting protective CD8 T cell responses, presumably because subunit Ags become insufficiently cross-presented by dendritic cells (DCs) and because the latter need to be activated to acquire competence for cross-priming. In this study, we show that CpG-Ag complexes overcome these limitations. OVA covalently linked to CpG-DNA (CpG-OVA complex), once it is efficiently internalized by DCs via DNA receptor-mediated endocytosis, is translocated to lysosomal-associated membrane protein 1 (LAMP-1)-positive endosomal-lysosomal compartments recently shown to display competence for cross-presentation.

Role of viral factor E3L in modified vaccinia virus ankara infection of human HeLa Cells: regulation of the virus life cycle and identification of differentially expressed host genes.

Modified vaccinia virus Ankara (MVA) is a highly attenuated virus strain being developed as a vaccine for delivery of viral and recombinant antigens. The MVA genome lacks functional copies of numerous genes interfering with host response to infection. The interferon resistance gene E3L encodes one important viral immune defense factor still made by MVA.

Modified vaccinia virus Ankara as antigen delivery system: how can we best use its potential?

Safety-tested modified vaccinia virus Ankara (MVA) has been established as a potent vector system for the development of candidate recombinant vaccines. The versatility of the vector system was recently demonstrated by the rapid production of experimental MVA vaccines for immunization against severe acute respiratory syndrome associated coronavirus. Promising results were also obtained in the delivery of Epstein-Barr virus or human cytomegalovirus antigens and from the clinical testing of MVA vectors for vaccination against immunodeficiency virus, papilloma virus, Plasmodium falciparum or melanoma.

Construction and isolation of recombinant MVA.

Modified vaccinia virus Ankara (MVA) is a valuable tool for the expression of recombinant genes used for such purposes as the study of protein functions or characterization of cellular and humoral immune responses. A major advantage of MVA is its clear safety record, and it can be handled under biosafety level 1 conditions. Despite its replication deficiency in human and most mammalian cells, MVA provides high-level gene expression and has proven to be immunogenic when delivering heterologous antigens in animals and humans.

Neutralization assay using a modified vaccinia virus Ankara vector expressing the green fluorescent protein is a high-throughput method to monitor the humoral immune response against vaccinia virus.

Vaccination against smallpox is again considered in order to face a possible bioterrorist threat, but the nature and the level of the immune response needed to protect a person from smallpox after vaccination are not totally understood. Therefore, simple, rapid, and accurate assays to evaluate the immune response to vaccinia virus need to be developed. Neutralization assays are usually considered good predictors of vaccine efficacy and more informative with regard to protection than binding assays.

Vaccinia vectors as candidate vaccines: the development of modified vaccinia virus Ankara for antigen delivery.

Vaccinia viruses engineered to express foreign genes are powerful vectors for production of recombinant proteins. Originating from highly efficacious vaccines securing world-wide eradication of smallpox, the most appealing use of vaccinia vectors is to serve as vaccine delivery system for heterologous antigens. Concerns about the safety of vaccinia virus have been addressed by the development of vectors based on attenuated viruses.

Replication of modified vaccinia virus Ankara in primary chicken embryo fibroblasts requires expression of the interferon resistance gene E3L.

Highly attenuated modified vaccinia virus Ankara (MVA) serves as a candidate vaccine to immunize against infectious diseases and cancer. MVA was randomly obtained by serial growth in cultures of chicken embryo fibroblasts (CEF), resulting in the loss of substantial genomic information including many genes regulating virus-host interactions. The vaccinia virus interferon (IFN) resistance gene E3L is among the few conserved open reading frames encoding viral immune defense proteins.

Human papillomavirus type 16 L1 capsomeres induce L1-specific cytotoxic T lymphocytes and tumor regression in C57BL/6 mice.

We analyzed capsomeres of human papillomavirus type 16 (HPV16) consisting of the L1 major structural protein for their ability to trigger a cytotoxic T-cell (CTL) response. To this end, we immunized C57BL/6 mice and used the L1(165-173) peptide for ex vivo restimulation of splenocytes prior to analysis ((51)Cr release assay and enzyme-linked immunospot assay [ELISPOT]). This peptide was identified in this study as a D(b)-restricted naturally processed CTL epitope by HPV16 L1 sequence analysis, major histocompatibility complex class I binding, and (51)Cr release assays following immunization of C57BL/6 mice with HPV16 L1 virus-like particles (VLPs).

Identification of vaccinia virus epitope-specific HLA-A*0201-restricted T cells and comparative analysis of smallpox vaccines.

Despite worldwide eradication of naturally occurring variola virus, smallpox remains a potential threat to both civilian and military populations. New, safe smallpox vaccines are being developed, and there is an urgent need for methods to evaluate vaccine efficacy after immunization. Here we report the identification of an immunodominant HLA-A*0201-restricted epitope that is recognized by cytotoxic CD8(+) T cells and conserved among Orthopoxvirus species including variola virus.

IL-4-induced arginase 1 suppresses alloreactive T cells in tumor-bearing mice.

We previously demonstrated that a specialized subset of immature myeloid cells migrate to lymphoid organs as a result of tumor growth or immune stress, where they suppress B and T cell responses to Ags. Although NO was required for suppression of mitogen activation of T cells by myeloid suppressor cells (MSC), it was not required for suppression of allogenic responses. In this study, we describe a novel mechanism used by MSC to block T cell proliferation and CTL generation in response to alloantigen, which is mediated by the enzyme arginase 1 (Arg1).