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Haruki Otsuka - One of the best experts on this subject based on the ideXlab platform.
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Mutation Hot Spots in the Canine Herpesvirus Thymidine Kinase Gene
Virus Genes, 2005Co-Authors: Shinya Yamada, Yasuhiro Takashima, Yasunobu Matsumoto, Haruki OtsukaAbstract:The guanine and cytosine content (GC-content) of alpha-Herpesvirus genes are highly variable despite similar genome structures. It is known that drug resistant HSV, which has the genome with a high GC-content (approximately 70%), commonly includes frameshift mutations in homopolymer stretches of guanine (G) and cytosine (C) within the thymidine kinase (TK) gene. However, whether such mutation hotspots exist in the TK gene of Canine Herpesvirus (CHV) which has a low GC-content was unknown. In this study, we investigated mutations in the TK gene of CHV. CHV was passaged in the presence of iodo-deoxyuridine (IDU), and IDU-resistant clones were isolated. In all IDU-resistant virus clones, mutations in the TK gene were observed. The majority of these mutations were frameshift mutations of an adenine (A) insertion or deletion within either of 2 stretches of eight A’s in the TK gene. It was demonstrated that CHV TK mutations frequently occur at a limited number of hot spots within long homopolymer nucleotide stretches.
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Canine Herpesvirus ORF2 is a membrane protein modified by N-linked glycosylation.
Virus research, 2002Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Hideyuki Nagasawa, Takeshi Mikami, Levi H. C. Makala, Haruki OtsukaAbstract:Canine Herpesvirus (CHV) ORF2, located downstream of the glycoprotein C (gC) gene, has homologues with some of the alphaHerpesviruses. To characterize CHV OFR2, a recombinant CHV carrying a LacZ gene in the ORF2 locus, and recombinant vaccinia virus expressing ORF2 protein were constructed. Northern blot analysis revealed ORF2 and a gamma2 class late gene, and its protein product was detectable in CHV-infected cells reacted with ORF2 protein antiserum. Tunicamycin and N-glycosidase F treatment revealed that the ORF2 protein was modified by N-linked glycosylation. Fractionation and immune fluorescence analyses of the CHV-infected cells showed the ORF2 as a membrane protein transportable to the surface of infected cells. In vitro, the ORF2 protein did not affect viral replication and cell-to-cell viral spreading. Present findings represent the first evidence pointing to the CHV ORF2 as a membrane protein modified by an N-linked glycosylation.
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Immunisation of dogs with a Canine Herpesvirus vector expressing Neospora caninum surface protein, NcSRS2
International journal for parasitology, 2000Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Haruki Otsuka, Hiroyasu Ikeda, Shiya Fukumoto, Hideyuki Nagasawa, Takeshi MikamiAbstract:In order to develop a vaccine against Neospora caninum in dogs, we constructed recombinant Canine Herpesvirus (CHV) expressing N. caninum surface protein, NcSRS2. Indirect immunofluorescence indicated that the antigenic structure of the recombinant NcSRS2 was similar to the authentic parasite protein. The dogs immunised with recombinant virus produced IgG antibody to N. caninum, and their sera recognised the parasite protein on Western blot. The dogs inoculated with recombinant virus showed no clinical symptoms and infectious CHV was not recovered from the dogs, suggesting that recombinant CHV expressing N. caninum proteins may lead to a vaccine against neosporosis in dogs.
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Attachment and penetration of Canine Herpesvirus 1 in non-permissive cells.
The Journal of veterinary medical science, 2000Co-Authors: Kazuo Nakamichi, Yasunobu Matsumoto, Kentaro Ohara, Haruki OtsukaAbstract:Canine Herpesvirus 1 (CHV-1) has a relatively narrow host cell range when compared to other alphaHerpesviruses. The early events of CHV-1 infection in a permissive Madin-Darby Canine kidney (MDCK) and non-permissive cell lines. In order to quantify attachment and penetration, were investigated quantitative competitive PCR (QCPCR) method was established for quantitation of CHV-1 DNA. In all non-permissive cells tested, no significant decrease in viral attachment was observed. When CHV-1 was treated with heparin, viral attachment to MDCK cells was reduced by 25% of the input CHV-1 attached to MDCK cells even in the presence of 50 microg/ml heparin. However, the attachment of CHV-1 to non-permissive cells was severely impaired by heparin treatment. In permissive MDCK cells, about 80% of attached CHV-1 penetrated into cells. However, only 4-10% of CHV-1 attached to non-permissive cells penetrated into cells. Our data indicated that CHV-1, like other Herpesviruses, attached to permissive MDCK cells through two mechanisms: the first one is through the interaction mediated by heparan sulfate (HS) on the cell surface and the second involves unidentified viral component and the cellular receptor. In contrast, the non-permissive cells lacked the cellular receptor for the second attachment mechanism and the defect in viral penetration into non-permissive cell might be related to the lack of the cellular receptor.
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Characterization of pseudorabies virus glycoprotein B expressed by Canine Herpesvirus.
The Journal of veterinary medical science, 1999Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Haruki OtsukaAbstract:A recombinant Canine Herpesvirus (CHV) which expressed glycoprotein B (gB) of pseudorabies virus (PrV) was constructed. The antigenicity of the PrV gB expressed by the recombinant CHV is similar to that of the native PrV. The expressed PrV gB was shown to be transported to the surface of infected cells as judged by an indirected immunofluorescence test. Antibodies raised in mice immunized with the recombinant CHV neutralized the infectivity of PrV in vitro. It is known that the authentic PrV gB exists as a glycoprotein complex, which consists of gBa, gBb and gBc. In MDCK cells, PrV gB expressed by the recombinant CHV was processed like authentic PrV gB, suggesting that the cleavage mechanism of PrV gB depends on a functional cleavage domain from PrV gB gene and protease from infected cells.
Xuenan Xuan - One of the best experts on this subject based on the ideXlab platform.
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Antiviral activity of lactoferrin against Canine Herpesvirus.
Antiviral research, 2003Co-Authors: Tetsuya Tanaka, Syogo Nakatani, Xuenan Xuan, Haruto Kumura, Ikuo Igarashi, Kei Ichi ShimazakiAbstract:Lactoferrin (LF) is an iron-binding protein that is found in milk and other mammalian secretions. We found that bovine lactoferrin (bLF) inhibited both the in vitro infection and replication of Canine Herpesvirus (CHV) in Madin-Darby Canine kidney (MDCK) cells. Incubation of CHV with bLF prevented subsequent infection of MDCK cells. Furthermore, proteins from CHV-infected MDCK cells were resolved by SDS-PAGE, and then bLF CHV-binding proteins were identified by far Western blotting. We demonstrated that the anti-CHV activity of bLF was due to its interaction with CHV as well as with MDCK cells. Both the apo- and holo-forms of bLF inhibited virus multiplication independently of their iron-withholding properties. We also demonstrated that human LF had anti-CHV activity. Our findings suggest that LF could be effective in dogs to provide protection against CHV infection.
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Canine Herpesvirus ORF2 is a membrane protein modified by N-linked glycosylation.
Virus research, 2002Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Hideyuki Nagasawa, Takeshi Mikami, Levi H. C. Makala, Haruki OtsukaAbstract:Canine Herpesvirus (CHV) ORF2, located downstream of the glycoprotein C (gC) gene, has homologues with some of the alphaHerpesviruses. To characterize CHV OFR2, a recombinant CHV carrying a LacZ gene in the ORF2 locus, and recombinant vaccinia virus expressing ORF2 protein were constructed. Northern blot analysis revealed ORF2 and a gamma2 class late gene, and its protein product was detectable in CHV-infected cells reacted with ORF2 protein antiserum. Tunicamycin and N-glycosidase F treatment revealed that the ORF2 protein was modified by N-linked glycosylation. Fractionation and immune fluorescence analyses of the CHV-infected cells showed the ORF2 as a membrane protein transportable to the surface of infected cells. In vitro, the ORF2 protein did not affect viral replication and cell-to-cell viral spreading. Present findings represent the first evidence pointing to the CHV ORF2 as a membrane protein modified by an N-linked glycosylation.
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Immunisation of dogs with a Canine Herpesvirus vector expressing Neospora caninum surface protein, NcSRS2
International journal for parasitology, 2000Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Haruki Otsuka, Hiroyasu Ikeda, Shiya Fukumoto, Hideyuki Nagasawa, Takeshi MikamiAbstract:In order to develop a vaccine against Neospora caninum in dogs, we constructed recombinant Canine Herpesvirus (CHV) expressing N. caninum surface protein, NcSRS2. Indirect immunofluorescence indicated that the antigenic structure of the recombinant NcSRS2 was similar to the authentic parasite protein. The dogs immunised with recombinant virus produced IgG antibody to N. caninum, and their sera recognised the parasite protein on Western blot. The dogs inoculated with recombinant virus showed no clinical symptoms and infectious CHV was not recovered from the dogs, suggesting that recombinant CHV expressing N. caninum proteins may lead to a vaccine against neosporosis in dogs.
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Characterization of pseudorabies virus glycoprotein B expressed by Canine Herpesvirus.
The Journal of veterinary medical science, 1999Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Haruki OtsukaAbstract:A recombinant Canine Herpesvirus (CHV) which expressed glycoprotein B (gB) of pseudorabies virus (PrV) was constructed. The antigenicity of the PrV gB expressed by the recombinant CHV is similar to that of the native PrV. The expressed PrV gB was shown to be transported to the surface of infected cells as judged by an indirected immunofluorescence test. Antibodies raised in mice immunized with the recombinant CHV neutralized the infectivity of PrV in vitro. It is known that the authentic PrV gB exists as a glycoprotein complex, which consists of gBa, gBb and gBc. In MDCK cells, PrV gB expressed by the recombinant CHV was processed like authentic PrV gB, suggesting that the cleavage mechanism of PrV gB depends on a functional cleavage domain from PrV gB gene and protease from infected cells.
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Biosynthesis and interaction of glycoproteins E and I of Canine Herpesvirus
Virus research, 1999Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Haruki OtsukaAbstract:Abstract In cells infected with Canine Herpesvirus (CHV), the mature form of glycoprotein E (gE) had a molecular weight of 94 kDa, and that of glycoprotein I (gI) had a broad range of molecular weights of 55–62 kDa. gE and gI formed a complex like gE and gI of other alphaHerpesviruses. When cells were infected with the gI minus mutant of CHV (gI/Z), the mature form of the 94 kDa gE was not formed, but a 76 kDa gE polypeptide was found. Similarly, no mature gI was formed in cells infected with the gE minus mutant of CHV (gE/Z), but a 40 kDa gI polypeptide was formed. When cells were coinfected with gE/Z and gI/Z, the molecular masses of gE and gI were increased from 76 to 94 kDa and from 40 to 55–62 kDa, respectively. We constructed vaccinia virus recombinants which expressed CHV gE or CHV gI. Only when cells were coinfected with both the vaccinia recombinant which expressed gE and the vaccinia recombinant which expressed gI, gE and gI were processed into their mature forms. Our results suggest that the presence of both gE and gI is necessary for efficient processing of the precursors of gE and gI to their mature forms.
Gerhard H. Reubel - One of the best experts on this subject based on the ideXlab platform.
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Suitability of Canine Herpesvirus as a vector for oral bait vaccination of foxes.
Veterinary microbiology, 2006Co-Authors: Gerhard H. Reubel, Jenny Pekin, John Wright, Nigel French, Tanja StriveAbstract:Studies were conducted to evaluate the feasibility of using Canine Herpesvirus (CHV) as a vaccine vector for bait-delivered oral vaccination of wild foxes. To test the viability of CHV in baits, CHV was freeze-dried, incorporated into different baits, stored, and the remaining viral infectivity tested in cell culture after varying periods of time at different storage temperatures. Experimental baits (mouse carcasses) and commercial baits (FOXOFF and PROBAIT) were prepared with either liquid or freeze-dried CHV and tested in two fox trials for their capacity to induce CHV-specific antibodies following oral baiting. Freeze-drying and storage temperatures below 0 degrees C had a stabilizing effect to virus infectivity. When stored at -20 degrees C, freeze-dried CHV retained its full infectivity for up to 3 months in PROBAIT baits, the remaining infectivity in FOXOFF baits was 100-fold less. Oral baiting with CHV induced antiviral serum antibodies in all vaccinated foxes (20/20). None of the vaccinated foxes became ill or shed infectious virus into the environment although viral DNA was detected in body secretions as evaluated by PCR. The results indicate that CHV can be freeze-dried and stored over extended periods of time without loosing much of its infectivity. This is the first report of CHV being used for oral bait vaccination of foxes. It appears that CHV is well suited for use as a recombinant vector for wild canids.
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Suitability of Canine Herpesvirus as a vector for oral bait vaccination of foxes.
Veterinary Microbiology, 2006Co-Authors: Gerhard H. Reubel, Jenny Pekin, John Wright, Nigel P. French, Tanja StriveAbstract:Abstract Studies were conducted to evaluate the feasibility of using Canine Herpesvirus (CHV) as a vaccine vector for bait-delivered oral vaccination of wild foxes. To test the viability of CHV in baits, CHV was freeze-dried, incorporated into different baits, stored, and the remaining viral infectivity tested in cell culture after varying periods of time at different storage temperatures. Experimental baits (mouse carcasses) and commercial baits (FOXOFF and PROBAIT) were prepared with either liquid or freeze-dried CHV and tested in two fox trials for their capacity to induce CHV-specific antibodies following oral baiting. Freeze-drying and storage temperatures below 0 °C had a stabilizing effect to virus infectivity. When stored at −20 °C, freeze-dried CHV retained its full infectivity for up to 3 months in PROBAIT baits, the remaining infectivity in FOXOFF baits was 100-fold less. Oral baiting with CHV induced antiviral serum antibodies in all vaccinated foxes (20/20). None of the vaccinated foxes became ill or shed infectious virus into the environment although viral DNA was detected in body secretions as evaluated by PCR. The results indicate that CHV can be freeze-dried and stored over extended periods of time without loosing much of its infectivity. This is the first report of CHV being used for oral bait vaccination of foxes. It appears that CHV is well suited for use as a recombinant vector for wild canids.
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Development of Canine Herpesvirus based antifertility vaccines for foxes using bacterial artificial chromosomes.
Vaccine, 2005Co-Authors: Tanja Strive, John Wright, Nigel P. French, Christopher M. Hardy, Nitin Nagaraja, Gerhard H. ReubelAbstract:Using bacterial artificial chromosome (BAC) technology, a Canine Herpesvirus (CHV)-based recombinant vaccine vector was produced for the development of an antifertility vaccine for foxes. Infectious viruses were recovered following transfection of canid cells with a BAC plasmid carrying the complete CHV genome. In vitro growth characteristics of BAC-derived viruses were similar to that of wildtype (wt)-CHV. Two recombinant antigens, fox zona pellucida protein subunit 3 (fZPC) and enhanced green fluorescent protein (EGFP) as control antigen, were inserted into thymidine kinase (TK) locus of the CHV genome and shown to be efficiently expressed in vitro. Inoculation of foxes with transgenic CHVs induced CHV specific antibodies, but was innocuous and failed to elicit transgene-specific antibody responses. Infectious virus or viral DNA was not detected in mucosal secretions or tissues of vaccinated foxes. The CHV-BAC system proved to be a quick and reliable method to manipulate the CHV genome. It will help to readily apply changes in the vector design in order to improve virus replication in vivo.
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CORTICOSTEROID TREATMENT DOES NOT REACTIVATE Canine Herpesvirus IN RED FOXES
Journal of wildlife diseases, 2004Co-Authors: Gerhard H. Reubel, Jenny Pekin, John Wright, Daryl Venables, Nigel P. FrenchAbstract:To study Canine Herpesvirus (CHV) reactivation from red foxes (Vulpes vulpes), 29 foxes with varying CHV antibody and CHV carrier status were treated with methylprednisolone acetate, a glucocorticosteroid drug with prolonged immunosuppressive effect in dogs. In the first experiment, 17 foxes with unknown CHV carrier status were treated once with methylprednisolone; in the second experiment, five foxes were treated twice, 4 mo after being intravenously CHV infected; and in the third experiment, six foxes were treated five times, 11 mo after peroral CHV infection. Infectious CHV was not isolated after treatment from either naturally or experimentally CHV-infected foxes or from untreated, CHV-seronegative in-contact foxes. Canine Herpesvirus DNA was not detectable in mucosal secretions or white blood cells of any of the foxes, whereas all trigeminal ganglia of experimentally CHV-infected foxes were polymerase chain reaction-positive. In CHV-seropositive foxes, anti-CHV antibody titers did not change with tim...
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Experimental infection of European red foxes (Vulpes vulpes) with Canine Herpesvirus.
Veterinary microbiology, 2001Co-Authors: Gerhard H. Reubel, Jenny Pekin, John Wright, Daryl Venables, Steven Zabar, Katrina Leslie, Terry L.w Rothwell, Lyn A. Hinds, Andrew L. BraidAbstract:We report on the pathogenicity of Canine Herpesvirus (CHV) for European red foxes. In the first experiment, we inoculated 10 adult foxes intravenously with a Canine isolate of CHV. All foxes became infected and shed CHV in saliva and genital secretions for up to 14 days post-inoculation (p.i.) as evaluated by PCR and/or by virus isolation. All foxes developed clinical signs such as fever, lethargy and evidence of respiratory tract disease. Two foxes died on day 6 p.i., one on day 7 p.i., and one fox was euthanased on day 6 p.i. Tissues taken from the four dead foxes were positive for CHV by PCR. The remaining six foxes recovered after approximately 14 days p.i. Virus particles with morphology typical of Herpesviruses were found by electron microscopy in the liver of an infected animal. All surviving foxes developed serum anti-CHV antibodies. In a second experiment, six foxes were dosed perorally with CHV and paired with six untreated controls. Neither the perorally dosed nor the in-contact control foxes developed clinical signs of disease. Infectious CHV was not isolated from any of the dosed or the in-contact foxes but all perorally-infected foxes and one of the in-contact foxes tested PCR-positive for CHV on several occasions p.i. All perorally-infected foxes, but none of the in-contact foxes, seroconverted. In summary, intravenous CHV inoculation caused a clinical disease in adult foxes much more severe than observed in experimentally-infected adult dogs. No clinical disease or virus spread was observed after peroral dosing although viral infection occurred as evidenced by seroconversion.
Yoshifumi Nishikawa - One of the best experts on this subject based on the ideXlab platform.
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Canine Herpesvirus ORF2 is a membrane protein modified by N-linked glycosylation.
Virus research, 2002Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Hideyuki Nagasawa, Takeshi Mikami, Levi H. C. Makala, Haruki OtsukaAbstract:Canine Herpesvirus (CHV) ORF2, located downstream of the glycoprotein C (gC) gene, has homologues with some of the alphaHerpesviruses. To characterize CHV OFR2, a recombinant CHV carrying a LacZ gene in the ORF2 locus, and recombinant vaccinia virus expressing ORF2 protein were constructed. Northern blot analysis revealed ORF2 and a gamma2 class late gene, and its protein product was detectable in CHV-infected cells reacted with ORF2 protein antiserum. Tunicamycin and N-glycosidase F treatment revealed that the ORF2 protein was modified by N-linked glycosylation. Fractionation and immune fluorescence analyses of the CHV-infected cells showed the ORF2 as a membrane protein transportable to the surface of infected cells. In vitro, the ORF2 protein did not affect viral replication and cell-to-cell viral spreading. Present findings represent the first evidence pointing to the CHV ORF2 as a membrane protein modified by an N-linked glycosylation.
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Immunisation of dogs with a Canine Herpesvirus vector expressing Neospora caninum surface protein, NcSRS2
International journal for parasitology, 2000Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Haruki Otsuka, Hiroyasu Ikeda, Shiya Fukumoto, Hideyuki Nagasawa, Takeshi MikamiAbstract:In order to develop a vaccine against Neospora caninum in dogs, we constructed recombinant Canine Herpesvirus (CHV) expressing N. caninum surface protein, NcSRS2. Indirect immunofluorescence indicated that the antigenic structure of the recombinant NcSRS2 was similar to the authentic parasite protein. The dogs immunised with recombinant virus produced IgG antibody to N. caninum, and their sera recognised the parasite protein on Western blot. The dogs inoculated with recombinant virus showed no clinical symptoms and infectious CHV was not recovered from the dogs, suggesting that recombinant CHV expressing N. caninum proteins may lead to a vaccine against neosporosis in dogs.
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Characterization of pseudorabies virus glycoprotein B expressed by Canine Herpesvirus.
The Journal of veterinary medical science, 1999Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Michiko Kimura, Haruki OtsukaAbstract:A recombinant Canine Herpesvirus (CHV) which expressed glycoprotein B (gB) of pseudorabies virus (PrV) was constructed. The antigenicity of the PrV gB expressed by the recombinant CHV is similar to that of the native PrV. The expressed PrV gB was shown to be transported to the surface of infected cells as judged by an indirected immunofluorescence test. Antibodies raised in mice immunized with the recombinant CHV neutralized the infectivity of PrV in vitro. It is known that the authentic PrV gB exists as a glycoprotein complex, which consists of gBa, gBb and gBc. In MDCK cells, PrV gB expressed by the recombinant CHV was processed like authentic PrV gB, suggesting that the cleavage mechanism of PrV gB depends on a functional cleavage domain from PrV gB gene and protease from infected cells.
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Biosynthesis and interaction of glycoproteins E and I of Canine Herpesvirus
Virus research, 1999Co-Authors: Yoshifumi Nishikawa, Xuenan Xuan, Haruki OtsukaAbstract:Abstract In cells infected with Canine Herpesvirus (CHV), the mature form of glycoprotein E (gE) had a molecular weight of 94 kDa, and that of glycoprotein I (gI) had a broad range of molecular weights of 55–62 kDa. gE and gI formed a complex like gE and gI of other alphaHerpesviruses. When cells were infected with the gI minus mutant of CHV (gI/Z), the mature form of the 94 kDa gE was not formed, but a 76 kDa gE polypeptide was found. Similarly, no mature gI was formed in cells infected with the gE minus mutant of CHV (gE/Z), but a 40 kDa gI polypeptide was formed. When cells were coinfected with gE/Z and gI/Z, the molecular masses of gE and gI were increased from 76 to 94 kDa and from 40 to 55–62 kDa, respectively. We constructed vaccinia virus recombinants which expressed CHV gE or CHV gI. Only when cells were coinfected with both the vaccinia recombinant which expressed gE and the vaccinia recombinant which expressed gI, gE and gI were processed into their mature forms. Our results suggest that the presence of both gE and gI is necessary for efficient processing of the precursors of gE and gI to their mature forms.
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Construction of Canine Herpesvirus Vector Expressing Foreign Genes Using a lacZ-TK Gene Cassette as a Double Selectional Marker
Virus Genes, 1998Co-Authors: Xuenan Xuan, Kotaro Tuchiya, Yoshifumi Nishikawa, Yasuhiro Takashima, Susumu Ueda, Takeshi Mikami, Ken Maeda, Naoaki Yokoyama, Haruki OtsukaAbstract:An improved method for constructing Canine Herpesvirus (CHV) recombinants expressing foreign genes by using the lacZ-TK gene cassette as a double selectional marker was developed. A recombinant CHV carrying the lacZ-TK gene at a targeted gene locus was constructed and used as a parental virus for generating new recombinants. The parental virus formed blue plaques and was sensitive to TK-specific drugs, while newly generated recombinants, in which the lacZ-TK gene was replaced with the desired foreign gene, become both resistant to the TK-specific drugs and formed white plaques. Recombinants were isolated by using the combination of drug selection and color selection. This improved method allows construction of recombinant CHV with great ease, because the drug selection can enrich the frequency of recombinant CHV from 0.01–0.1% to 10–80%. This method was employed to construct a recombinant CHV that expressed rabies virus (RV) glycoprotein (G protein).
Eric C. Ledbetter - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of topical ophthalmic ganciclovir gel for the treatment of dogs with experimentally induced ocular Canine Herpesvirus-1 infection.
American journal of veterinary research, 2018Co-Authors: Eric C. Ledbetter, Amanda M. Nicklin, Chloe B. Spertus, Matthew R. Pennington, Gerlinde R. Van De Walle, Hussni O. MohammedAbstract:OBJECTIVE To determine the in vitro half maximal effective concentration (EC50) of ganciclovir for Canine Herpesvirus-1 (CHV-1) and to evaluate the efficacy of ganciclovir ophthalmic gel in dogs wi...
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Effects of topical ocular application of 1% trifluridine ophthalmic solution in dogs with experimentally induced recurrent ocular Canine Herpesvirus-1 infection.
American journal of veterinary research, 2016Co-Authors: Chloe B. Spertus, Hussni O. Mohammed, Eric C. LedbetterAbstract:OBJECTIVE To determine the effects of topical ocular application of 1% trifluridine ophthalmic solution in dogs with experimentally induced recurrent ocular Canine Herpesvirus-1 (CHV-1) infection. ANIMALS 10 specific pathogen–free Beagles. PROCEDURES 12 months prior to the beginning of the randomized, masked, placebo-controlled 30-day trial, latent ocular CHV-1 infection was experimentally induced in each dog by topical ocular inoculation of both eyes with a field strain of CHV-1. Recurrent ocular CHV-1 infection was induced by oral administration of prednisolone for 7 days (starting day 1). Starting on the fourth day of prednisolone administration, each dog received 1% trifluridine solution or artificial tears (placebo) topically in both eyes 6 times daily for 2 days and then 4 times daily for 12 days. Ophthalmic examinations were performed every 2 days, and ocular disease scores were calculated. Ocular samples for CHV-1 PCR assays and blood samples for clinicopathologic analyses and assessment of CHV-1 ...
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Effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with Canine Herpesvirus-1.
Veterinary Microbiology, 2014Co-Authors: Amanda M. Nicklin, Margaret C. Mcentee, Eric C. LedbetterAbstract:Latent Canine Herpesvirus-1 (CHV-1) infections are common in domestic dogs, but stimuli causing viral reactivation and recrudescent disease are poorly understood. Immunosuppressive pharmaceuticals are currently the only experimentally established triggers for recurrent ocular CHV-1 infection in dogs; however, ocular CHV-1 shedding has been reported clinically following strontium-90 beta radiotherapy of the ocular surface and it has been speculated that radiotherapy can directly induce viral reactivation. Strontium-90 is used as a beta radiation source for the treatment of a variety of neoplastic and immune-mediated Canine ocular surface diseases. In the present study, the effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with CHV-1 were evaluated. Ten mature dogs with experimentally induced latent CHV-1 infections were randomly divided into two groups: one group received a single fraction 50 Gy radiation dose in one application from a strontium-90 ophthalmic applicator and the second group received sham radiotherapy. Dogs were then monitored for 45 days for recurrent ocular CHV-1 infection using clinical and virological outcome measures. Clinical ophthalmic examinations, ocular sample CHV-1 PCR assays, and serum CHV-1 virus neutralizing antibody assays were performed at specified intervals. No abnormalities suggestive of recurrent CHV-1 ocular disease were observed on clinical examination in any dog during the study. Ocular viral shedding was not detected and CHV-1 virus neutralizing titers remained stable in all dogs. A single fraction 50 Gy radiation dose administered to the ocular surface by strontium-90 beta radiotherapy did not result in detectable recurrent ocular CHV-1 infection in mature dogs with experimentally induced latent infection.
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frequency of spontaneous Canine Herpesvirus 1 reactivation and ocular viral shedding in latently infected dogs and Canine Herpesvirus 1 reactivation and ocular viral shedding induced by topical administration of cyclosporine and systemic administrati
American Journal of Veterinary Research, 2012Co-Authors: Eric C. Ledbetter, Erotides C Da Silva, Edward J. Dubovi, Wayne S. SchwarkAbstract:Objective—To determine the frequency of spontaneous Canine Herpesvirus-1 (CHV-1) reactivation and ocular viral shedding in latently infected dogs and the effect of topical ocular administration of cyclosporine. Animals—8 mature Beagles with experimentally induced latent CHV-1 infection. Procedures—Following induction of primary ocular CHV-1 infection, the presence of reactivatable CHV-1 latency was confirmed by systemically administering prednisolone to the dogs. Dogs were then monitored for 36 weeks via clinical examination and conjunctival sample CHV-1 PCR assay performed at 4-day intervals and CHV-1 virus neutralization antibody assay performed at 2-week intervals. During weeks 16 to 32, dogs were administered 0.2% cyclosporine ointment in both eyes twice daily and blood cyclosporine concentrations were monitored. During weeks 33 to 36, the presence of reactivatable CHV-1 latency was reconfirmed via systemic administration of prednisolone. Results—Reactivation of latent CHV-1 was not detected via clini...
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Effects of cyclophosphamide myelosuppression in adult dogs with latent Canine Herpesvirus-1 infection.
Veterinary microbiology, 2012Co-Authors: Patricia Mundy, Erotides C Da Silva, Eric C. LedbetterAbstract:Latent Canine Herpesvirus-1 (CHV-1) infection is common in domestic dogs, but triggers for viral reactivation and recrudescent CHV-1 disease are poorly understood. Cyclophosphamide is a potent immunosuppressive and myelosuppressive agent used for the therapy of a variety of neoplastic and immune-mediated Canine disorders. Cyclophosphamide (200mg/m(2)) was administered to mature dogs latently infected with CHV-1 to determine its potential to induce recurrent CHV-1 disease and viral shedding. Non-infected dogs and dogs recovered from experimental primary ocular CHV-1 infection with experimentally confirmed latent CHV-1 infection were divided into groups and administered cyclophosphamide or placebo. Dogs were monitored for myelosuppression and viral reactivation for 28days using clinical and virological outcome measures. Clinical ophthalmic and in vivo ocular confocal microscopic examinations were performed at intervals. Samples were collected for CHV-1 polymerase chain reaction (PCR), CHV-1 virus neutralizing (VN) antibody, and hemogram assays. Myelosuppression (i.e., decreased total leukocyte, segmented neutrophil, and erythrocyte counts) was detected on study day 7 in dogs administered cyclophosphamide, but not dogs administered placebo. There were no abnormalities suggestive of recurrent CHV-1 ocular disease during clinical ophthalmic or in vivo confocal microscopic examination in any dogs during the study. Ocular CHV-1 shedding was not detected by PCR and CHV-1 VN titers remained stable in all dogs. Following study conclusion, the presence of reactivatable latency was reconfirmed in the infected dogs by administering systemic prednisolone. Myelosuppression elicited by a single dose of cyclophosphamide does not result in detectable recurrent ocular CHV-1 infection in adult dogs with experimentally induced latent CHV-1 infection.
