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At least 127 records · Page 7Linked to original sources
PubMed1990

Virus-specific early antigen expressed in the nucleus of cowpox virus-infected cells.

Two monoclonal antibodies (MAbs) were obtained from BALB/c mice immunized with cowpox virus (CPV)-infected cells cultured in the presence of cytosine-1-beta-D-arabinofuranosyl-HCl (Ara C). In the immunofluorescence test, the specific antigen reacting with these MAbs was restricted almost entirely to the nucleus in CPV-infected cells in the presence of Ara C at any time. On the other hand, in CPV-infected cells in the absence of Ara C, the antigen was first detectable within the nucleus 2 h after infection and migrated to the cytoplasm as the infection proceeded. On immunoblotting, only one component with an Mr of 27K was detected 2 to 24 h after infection of cells with CPV in either the presence or absence of Ara C. The antigen was also detected in vaccinia virus-infected cells, but not in any mock-infected cells nor in any virions purified from infected cells. These results suggest that the antigen reacting with the MAbs is virus-specific and a non-structural early antigen.

Animals↗
PubMed2000

Ectromelia, vaccinia and cowpox viruses encode secreted interleukin-18-binding proteins.

Interleukin-18 (IL-18) is a proinflammatory cytokine that plays a key role in the activation of natural killer and T helper 1 cell responses principally by inducing interferon-gamma (IFN-gamma). Human and mouse secreted IL-18-binding proteins (IL-18BPs) have recently been described which block IL-18 activity but have no sequence similarity to membrane IL-18 receptors. Several poxvirus genes encode proteins with sequence similarity to IL-18BPs. Here we show that vaccinia, ectromelia and cowpox viruses secrete from infected cells a soluble IL-18BP (vIL-18BP) that may modulate the host antiviral response. The ectromelia virus protein was found to block NF-kappaB activation and induction of IFN-gamma in response to IL-18. The highly attenuated vaccinia virus modified virus Ankara encodes IL-18-binding activity, and thus deletion of the vIL-18BP may improve further the safety and immunogenicity of this promising human vaccine candidate. We confirm that molluscum contagiosum virus, a molluscipoxvirus that produces small skin tumours in immunocompetent individuals and opportunistic infections in immunodeficient AIDS patients, also encodes a related, larger vIL-18BP (gene MC54L). This protein may contribute to the lack of inflammatory response characteristic of molluscum contagiosum virus lesions. The expression of vIL-18BPs by distinct poxvirus genera that cause local or general viral dissemination, or persistent or acute infections in the host, emphasizes the importance of IL-18 in response to viral infections.

Amino Acid Sequence↗
PubMed1993

Cowpox can mimic anthrax.

We report a patient suffering from cowpox infection, in whom the clinical features mimicked those of anthrax. The infection may have been acquired as a result of contact with a rodent.

Adolescent↗
PubMed1998

Activation of caspases in pig kidney cells infected with wild-type and CrmA/SPI-2 mutants of cowpox and rabbitpox viruses.

The cowpox virus (CPV) CrmA and the equivalent rabbitpox virus (RPV) SPI-2 proteins have anti-inflammatory and antiapoptosis activity by virtue of their ability to inhibit caspases, including the interleukin-1beta-converting enzyme (ICE; caspase-1). Infection of LLC-PK1 pig kidney cells with a CPV CrmA mutant, but not with wild-type (wt) CPV, results in the induction of many of the morphological features of apoptosis (C. A. Ray and D. J. Pickup, Virology 217:384-391, 1996). In our study, LLC-PK1 cells infected with CPV delta crmA, but not those infected with wt CPV, showed induction of poly(ADP-ribose) polymerase (PARP)- and lamin A-cleaving activities and processing of the CPP32 (caspase-3) precursor to a mature 18-kDa form. Surprisingly, infection of LLC-PK1 cells with either wt RPV (despite the presence of the SPI-2 protein) or RPV delta SPI-2 resulted in cleavage activity against PARP and lamin A and the appearance of the mature subunit of CPP32/caspase-3. The biotinylated specific peptide inhibitor Ac-Tyr-Val-Lys(biotinyl)-Asp-2,6-dimethylbenzoyloxymethylketone [AcYV(bio)KD-aomk] labeled active caspase subunits of 18, 19, and 21 kDa in extracts from LLC-PK1 cells infected with CPV delta crmA, wt RPV, or RPV delta SPI-2 but not wt CPV. Mixed infection of LLC-PK1 cells with wt RPV and wt CPV gave no PARP-cleaving activity, and all PARP cleavage mediated by SPI-2 and CrmA mutants of RPV and CPV, respectively, could be eliminated by coinfection with wt CPV. These results suggest that the RPV SPI-2 and CPV CrmA proteins are not functionally equivalent and that CrmA, but not SPI-2 protein, can completely prevent apoptosis in LLC-PK1 cells under these conditions.

Animals↗
PubMed1999

Myxoma virus Serp2 is a weak inhibitor of granzyme B and interleukin-1beta-converting enzyme in vitro and unlike CrmA cannot block apoptosis in cowpox virus-infected cells.

The Serp2 protein encoded by the leporipoxvirus myxoma virus is essential for full virulence (F. Messud-Petit, J. Gelfi, M. Delverdier, M. F. Amardeilh, R. Py, G. Sutter, and S. Bertagnoli, J. Virol. 72:7830-7839, 1998) and, like crmA of cowpox virus (CPV), is reported to inhibit the interleukin-1beta-converting enzyme (ICE, caspase-1) (F. Petit, S. Bertagnoli, J. Gelfi, F. Fassy, C. Boucraut-Baralon, and A. Milon, J. Virol. 70:5860-5866, 1996). Serp2 and CrmA both contain Asp at the P1 position within the serpin reactive site loop and yet are only 35% identical overall. Serp2 protein was cleaved by ICE but, unlike CrmA, did not form a stable complex with ICE that was detectable by native gel electrophoresis. Attempts to covalently cross-link ICE-serpin inhibitory complexes were successful with CrmA, but no complex between ICE and Serp2 was visible after cross-linking. Purified His10-tagged Serp2 protein was a relatively poor inhibitor of ICE, with a Ki of 80 nM compared to 4 pM for CrmA. Serp2 protein resembled CrmA in that a stable complex with the serine proteinase granzyme B was detectable after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, Serp2 was less effective at inhibiting granzyme B activity (Ki = 420 nM) than CrmA (Ki = 100 nM). Finally, Serp2 was tested for the ability to replace CrmA and inhibit apoptosis in LLC-PK1 cells infected with a CPV recombinant deleted for CrmA but expressing Serp2. Unlike wild-type-CPV-infected cells, apoptosis was readily observed in cells infected with the recombinant virus, as indicated by the induction of both nuclear fragmentation and caspase-mediated cleavage of DEVD-AMC [acetyl-Asp-Glu-Val-Asp-(amino-4-methyl coumarin)]. These results indicate that Serp2 is unable to functionally substitute for CrmA within the context of CPV and that the inhibition spectra for Serp2 and CrmA are distinct.

Amino Acid Sequence↗
PubMed2000

Animals, public health and the example of cowpox.

Public attitudes towards animals are often contradictory. In developed countries where the problem of food security has been solved to a large degree, public concern is concentrated on food safety and animal welfare, along with a debate on the social status of both domestic and wild animals. Zoonoses are often the focal point of these concerns. In developing countries (which often have the greatest biodiversity), wildlife constitutes an uncontrollable source of often unknown zoonoses. The authors attempt to analyse the link between animals and public health. Special attention is given to the example of cowpox, a disease which has been recognised as a zoonosis for more than two centuries but the epidemiology of which has recently been rediscovered.

Animal Husbandry↗
PubMedDate not supplied

[Reproduction of cowpox virus strain EP-2 isolated from an elephant in primary fibroblast cultures and chorion-allantoic chick embryos].

Electron microscopy was used to study the reproduction of cowpox virus strain EP-2 in the cells of a primary fibroblast cultures (PFC) and chorion-allantoic membrane (CAM) of chick embryos (CE). The sequential stages of viral morphogenesis and the structure of A-type inclusions were described. The parameters of viral reproduction in PFC and CE CAM were compared. The formation of crystalloid tubular structures in PFC, unusual electron dense inclusions in the cells of CE CAN, and different variants of A-type inclusions in the cells of a pock was found. The histological and ultrastructural characteristics of pocks in CE CAM are described.

Animals↗
PubMed1995

Human IL-1 beta processing and secretion in recombinant baculovirus-infected Sf9 cells is blocked by the cowpox virus serpin crmA.

Biologically active, mature IL-1 beta (mIL-1 beta) is released from activated monocytes after proteolytic processing from an inactive precursor (pIL-1 beta). IL-1 beta converting enzyme (ICE), the first member of a newly discovered family of cysteine proteinases, is required for this processing event. The cleaved cytokine is released from monocytes by an unknown mechanism which does not employ a standard hydrophobic signal sequence. As in mammalian fibroblasts, insect Sf9 cells do not normally process or secrete human IL-1 beta. The expression of active ICE enables Sf9 cells to process 31-kDa pIL-1 beta correctly at Asp27 and Asp116, and to export 17.5-kDa mIL-1 beta. The recombinant heterodimeric human enzyme purified from Sf9 cells possesses a sp. act. of 2.9 +/- 0.5 x 10(6) U/mg and is indistinguishable from native ICE with regard to its subunit composition and catalytic properties. In this system, co-expression of the cowpox virus crmA gene, an extremely potent serpin inhibitor of ICE (Ki < 7 pM), inhibits ICE activation completely and blocks pIL-1 beta processing and mIL-1 beta secretion by approximately 95%. The results indicate that ICE, in addition to its processing function, facilitates the transport of IL-1 beta across the plasma membrane.

Amino Acid Sequence↗
PubMed1994

Inhibition of interleukin-1 beta converting enzyme by the cowpox virus serpin CrmA. An example of cross-class inhibition.

We reported previously that human interleukin-1 beta converting enzyme (ICE) is regulated by the CrmA serpin encoded by cowpox virus. We now report the mechanism and kinetics of this unusual inhibition of a cysteine proteinase by a member of the serpin superfamily previously thought to inhibit serine proteinase only. CrmA possesses several characteristics typical of a number of inhibitory serpins. It is conformationally unstable, unfolding around 3 M urea, and stable to denaturation in 8 M urea upon complex formation with ICE. CrmA rapidly inhibits ICE with an association rate constant (kon) of 1.7 x 10(7) M-1 s-1, forming a tight complex with an equilibrium constant for inhibition (Ki) of less than 4 x 10(-12) M. These data indicate that CrmA is a potent inhibitor of ICE, consistent with the dramatic effects of CrmA on modifying host responses to virus infection. The inhibition of ICE by CrmA is an example of a "cross-class" interaction, in which a serpin inhibits a non-serine proteinase. Since CrmA possesses characteristics shared by inhibitors of serine proteinases, we presume that ICE, though it is a cysteine proteinase, has a substrate binding geometry strikingly close to that of serine proteinases. We reason that it is the substrate binding geometry, not the catalytic mechanism of a proteinase, that dictates its reactivity with protein inhibitors.

Amino Acid Sequence↗
PubMed1996

Occurrence of cowpox-like lesions in cattle in Israel.

Two different clinical forms of cowpox infection, which occurred sporadically in one dairy herd and one beef herd, are described. The agent was identified by virologic test and by electron microscopy, when a characteristic orthopoxvirus was noted. No systemic illness was diagnosed with any of the two forms and recovery was observed in 3-4 weeks. The epizootiology of the infection is discussed.

Animals↗
PubMed1984

Cross-reactivity between cowpox and vaccinia viruses with monoclonal antibodies. Brief report.

Hybridoma cell lines producing monoclonal antibodies against cowpox virus (CPV) and vaccinia virus (VV) were established to examine the specific and cross-reactive antigenic determinants of these viruses. Monoclonal antibodies against CPV (LB red strain) and VV (Lister strain and Ikeda strain) were classified into several groups on the basis of the results of immunofluorescence and haemagglutination inhibition tests. It was suggested that the groups defined above include the group of antibodies reacting with each of known major antigens of poxvirus, i.e. nucleoprotein (NP) antigen, heat labile and stable complex (LS) antigen, haemagglutinin (HA), cell surface antigen (CSA) and type A inclusion body (A).

Antibodies, Monoclonal↗
PubMed1986

Polypeptide analysis with monoclonal antibodies of A type inclusion bodies induced by cowpox virus.

The antigen in A type inclusion bodies (ATIB) induced by cowpox virus (CPV) was examined by immunofluorescent staining with monoclonal antibodies and polypeptide analysis. In the immunofluorescence (IF) test, these monoclonal antibodies reacted only with cytoplasmic inclusion bodies in cells infected with CPV. The fluorescence became detectable in the cells 6-9 hours after infection with CPV. No fluorescence was detectable in cells infected with CPV in the presence of cytosine-I-beta-D-arabinofuranosyl-HCl (Ara C) or in cells infected with other poxviruses, such as vaccinia virus (VV) or Shope fibroma virus (SFV). On Western blotting and immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), only one component with a molecular weight of about 160,000 (160 K) was detected in CPV-infected cells. This 160 K polypeptide was first detectable 12 hours after infection of cells with CPV, and was not detectable in infected cells in the presence of Ara C. The 160 K polypeptide was not detected in cells infected with VV or SFV, or in virions purified from CPV-, VV- or SFV-infected cells.

Animals↗
PubMed1986

Cross-reactivity among cowpox, ectromelia and vaccinia viruses with monoclonal antibodies recognizing distinct antigenic determinants in A-type inclusion bodies.

Several monoclonal antibodies recognizing distinct antigenic determinants in A-type inclusion bodies (ATIB) induced by cowpox virus (CPV) were obtained to examine the cross-reactivity among various strains of poxviridae, comprising CPV, ectromelia virus (EV), vaccinia virus (VV) and Shope fibroma virus (SFV). The monoclonal antibodies were classified into at least 3 groups on the basis of the results of an immunofluorescence test and immunoblotting; i. e., strain-specific, CPV and EV-specific and Orthopoxvirus (CPV, EV and VV)-specific antibodies. Differences were found between the antigenic determinants of ATIB of LB strains (LB red and LB white) and other strains (Amsterdam, 53, 58 and 60) of CPV and also between those of ATIB of CPV and EV. An interesting finding was that VV also produces the antigen analogous to that associated with ATIB in CPV- and EV-infected cells despite the absence of morphologically defined ATIB.

Antibodies, Monoclonal↗
PubMed1977

Cellular proteases increased in paramyxovirus (Sendai virus) carrier cells possibly responsible for enhanced formation of cowpox virus-specific cell surface antigen.

Cowpox virus (CPV) growth and its S-ag (cell surface antigen) formation in HVJ (Sendai virus) carrier cells pre-treated with Actinomycin D or Puromycin were not affected as much as those in parent cells. These suggest the different cellular functions of carrier cells. The activity of carrier cell extracts causing a characteristic degradation of CPV reacted with them in vitro disappeared after the pre-incubation of extracts with hemoglobin or casein. Measurements of cellular protease activities including lysosomal enzymes demonstrated significant increases in the carrier cell extracts compared to those in parent cells; The CPV, thus reacted in vitro with the extracts or lysosomal fraction from carrier cells, acquired more rapidly and markedly the enhanced ability of S-ag formation parallel to virus infectivity alteration in the reaction. These results indicate that the enhancement of CPV S-ag formation in the HVJ carrier cells may be due to their increased cellular enzymes, possibly proteolytic ones, capable of promoting the first step of CPV uncoating or degradation in the cells.

Acid Phosphatase↗
PubMed1989

Inhibition of an inflammatory response is mediated by a 38-kDa protein of cowpox virus.

The Brighton Red (BR) strain of cowpox virus induces a flat, bright red pock on the chorioallantoic membrane (CAM) of the 12-day-old chick embryo. In contrast, mutants with a deleted 38K gene (which is located 31 to 32 kb from the right-hand end of the virus genome) induced a raised, white, and opaque pock. During the first 24-hr p.i., both CPV-BR and the 38K deletion mutants replicated similarly in the CAM of the chick embryo, as indicated by immunocytochemical detection of similar amounts of virus antigen. By 48 hr p.i., the pocks induced by the mutant and CPV-BR are strikingly different. The pocks induced by the 38K deletion mutants were infiltrated by large numbers of heterophils and macrophages, which correlated with a reduction in the levels of virus antigen and virus infectivity. The CPV-BR pock had an absence of inflammatory cells and increased levels of virus antigen and infectivity. By 72 hr p.i., many of the pocks induced by the mutant were undergoing resolution of the virus infection, as indicated by further decrease of virus antigen and visible signs of healing, whereas CPV-BR pocks continued to be a site of active viral replication. These data are consistent with a model where this 38-kDa protein directly or indirectly inhibits the generation of chemotactic molecules which are elicited during virus replication in the CAM or, alternatively, blocks the interaction of these molecules with cells of the host inflammatory response.

Animals↗
PubMed1979

Antibody studies in natural bovine cowpox.

Serological studies on cows recovered from natural cowpox indicated that Haemagglutinin-Inhibiting (HAI) antibody persisted for at least 27 weeks, and Virus Neutralizing (VN) antibody persisted for at least 98 weeks.

Animals↗
PubMed2003

Practical synthesis of D- and l-2-cyclopentenone and their utility for the synthesis of carbocyclic antiviral nucleosides against orthopox viruses (smallpox, monkeypox, and cowpox virus).

Highly efficient and practical methodology for the syntheses of D- and l-4,5-O-isopropylidene-2-cyclopentenone (9 and 22), versatile intermediates for the synthesis of carbocyclic nucleosides, have been developed via a ring-closing metathesis reaction from d-ribose in eight steps. The utility of D- and l-4,5-O-isopropylidene-2-cyclopentenone is demonstrated by their application for the preparation of D-cyclopentyl-6-azauridine 12 and D-cyclopentenyl-5-halocytosine nucleosides (33-35) using Mitsunobu reaction to introduce pyrimidine bases as potential antiviral agents. Preliminary antiviral activity against orthopox viruses (smallpox, monkeypox, and cowpox virus) of the synthesized nucleosides are described.

Antiviral Agents↗