The Experts below are selected from a list of 375 Experts worldwide ranked by ideXlab platform
Walter Fuchs - One of the best experts on this subject based on the ideXlab platform.
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replication characteristics of Infectious Laryngotracheitis virus in the respiratory and conjunctival mucosa
Avian Pathology, 2014Co-Authors: Vishwanatha Reddy Avalakuppa Papi Reddy, Walter Fuchs, Lennert Steukers, Yewei Li, Alain Vanderplasschen, Hans NauwynckAbstract:Avian Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus of poultry that is spread worldwide. ILTV enters its host via the respiratory tract and the eyes. Although ILTV has been known for a long time, the replication characteristics of the virus in the respiratory and conjunctival mucosa are still poorly studied. To study these characteristics, two in vitro explant models were developed. Light microscopy and fluorescent terminal deoxynucleotidyl transferase dUTP nick end-labelling staining were used to evaluate the viability of mucosal explants, which were found to be viable up to the end of the experiment at 96 h of cultivation. The tracheal and conjunctival mucosal explants were inoculated with ILTV and collected at 0, 24, 48 and 72 h post inoculation (p.i.). ILTV spread in a plaque-wise manner in both mucosae. A reproducible quantitative analysis of this mucosal spread was evaluated by measuring plaque numbers, plaque latitude and invasion depth underneath the basement membrane. No major ...
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Identification and functional analysis of the small membrane-associated protein pUL11 of Avian Infectious Laryngotracheitis virus.
Virus research, 2011Co-Authors: Walter Fuchs, Jutta Veits, Harald Granzow, Thomas C MettenleiterAbstract:pUL11 is a highly conserved, small, acylated, membrane-associated tegument protein of herpesviruses. It is involved in final envelopment of nascent virions in the cytoplasm, although the precise mechanism is still unknown. By screening of mouse monoclonal antibodies (mAb) raised against purified particles of Infectious Laryngotracheitis virus (ILTV) of chickens (Veits et al., 2003a), we identified two mAb recognizing the 15 kDa UL11 protein (pUL11) of this Avian alphaherpesvirus. These mAb permitted detection and precise localization of pUL11 in mature ILT virions, as well as in the cytoplasm of infected chicken cells by Western blot analyses, indirect immunofluorescence tests, and immunoelectron microscopy. For investigation of gene function UL11-deleted ILTV recombinants were generated. Like its homologues in several other alphaherpesviruses, ILTV-pUL11 was shown to be nonessential for productive virus replication. However, compared to wild-type and UL11 rescued ILTV the deletion mutants exhibited significantly reduced virus yields and moderately impaired spread in cell culture. In the absence of pUL11, electron microscopy of infected cells revealed accumulations of tegument proteins with nucleocapsids, and marked distortions of Golgi membranes in the cytoplasm, which obviously inhibited the formation of mature, enveloped virus particles. Taken together, our results demonstrate that pUL11 is relevant for secondary envelopment of ILTV, and confirm functional conservation of this protein in herpesviruses. The now available unique pUL11-specific mAb will help to further analyze this function, which is presumably mediated by physical interactions with other viral gene products, in cultured cells and in the natural animal host of ILTV.
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molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an econom- ically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infec- tion of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phe- notype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been eluci- dated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suit- able for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been iden- tified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines. Infectious Laryngotracheitis virus / DNA sequence / monoclonal antibodies / recombinant live- virus vaccines / viral vectors
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the ul47 gene of Avian Infectious Laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Jens Peter Teifke, Thomas C Mettenleiter, Walter FuchsAbstract:The genome of Infectious Laryngotracheitis virus (ILTV) exhibits several differences from those of other Avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3'-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.
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identification of transcripts and protein products of the ul31 ul37 ul46 ul47 ul48 ul49 and us4 gene homologues of Avian Infectious Laryngotracheitis virus
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Thomas C Mettenleiter, Walter FuchsAbstract:In the present study, the transcription and protein expression of seven genes of Infectious Laryngotracheitis virus (ILTV) were investigated: UL31 and UL37 possess homologues in all known Avian and mammalian herpesviruses, whereas UL46–UL49 and US4 are only conserved in most alphaherpesviruses. A peculiarity of the ILTV genome is the translocation of UL47 from the unique long region to a position upstream of US4 within the unique short region. Northern blot analyses revealed that all of the analysed genes were transcribed most abundantly during the late (γ) phase of replication, but the only true late (γ2) gene was UL47. Using monospecific rabbit antisera, the protein products of all of the genes could be detected and localized in ILTV-infected cells. Considerable amounts of the UL31, UL47 and UL48 gene products were found in the cell nuclei, whereas the other proteins were restricted largely to the cytoplasm. Like the respective tegument proteins of other herpesviruses, the UL37 and UL46–UL49 gene products of ILTV were incorporated into virus particles, whereas the UL31 protein and the glycoprotein encoded by US4 (gG) were not detectable in purified virions. It was also demonstrated that the UL48 protein of ILTV is able to activate an alphaherpesvirus immediate-early gene promoter, which is also a typical feature of other UL48 homologues. Taken together, these results indicate that the functions of all of the investigated ILTV proteins are related to those of their homologues in other alphaherpesviruses.
Thomas C Mettenleiter - One of the best experts on this subject based on the ideXlab platform.
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Identification and functional analysis of the small membrane-associated protein pUL11 of Avian Infectious Laryngotracheitis virus.
Virus research, 2011Co-Authors: Walter Fuchs, Jutta Veits, Harald Granzow, Thomas C MettenleiterAbstract:pUL11 is a highly conserved, small, acylated, membrane-associated tegument protein of herpesviruses. It is involved in final envelopment of nascent virions in the cytoplasm, although the precise mechanism is still unknown. By screening of mouse monoclonal antibodies (mAb) raised against purified particles of Infectious Laryngotracheitis virus (ILTV) of chickens (Veits et al., 2003a), we identified two mAb recognizing the 15 kDa UL11 protein (pUL11) of this Avian alphaherpesvirus. These mAb permitted detection and precise localization of pUL11 in mature ILT virions, as well as in the cytoplasm of infected chicken cells by Western blot analyses, indirect immunofluorescence tests, and immunoelectron microscopy. For investigation of gene function UL11-deleted ILTV recombinants were generated. Like its homologues in several other alphaherpesviruses, ILTV-pUL11 was shown to be nonessential for productive virus replication. However, compared to wild-type and UL11 rescued ILTV the deletion mutants exhibited significantly reduced virus yields and moderately impaired spread in cell culture. In the absence of pUL11, electron microscopy of infected cells revealed accumulations of tegument proteins with nucleocapsids, and marked distortions of Golgi membranes in the cytoplasm, which obviously inhibited the formation of mature, enveloped virus particles. Taken together, our results demonstrate that pUL11 is relevant for secondary envelopment of ILTV, and confirm functional conservation of this protein in herpesviruses. The now available unique pUL11-specific mAb will help to further analyze this function, which is presumably mediated by physical interactions with other viral gene products, in cultured cells and in the natural animal host of ILTV.
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molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an econom- ically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infec- tion of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phe- notype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been eluci- dated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suit- able for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been iden- tified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines. Infectious Laryngotracheitis virus / DNA sequence / monoclonal antibodies / recombinant live- virus vaccines / viral vectors
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the ul47 gene of Avian Infectious Laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Jens Peter Teifke, Thomas C Mettenleiter, Walter FuchsAbstract:The genome of Infectious Laryngotracheitis virus (ILTV) exhibits several differences from those of other Avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3'-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.
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identification of transcripts and protein products of the ul31 ul37 ul46 ul47 ul48 ul49 and us4 gene homologues of Avian Infectious Laryngotracheitis virus
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Thomas C Mettenleiter, Walter FuchsAbstract:In the present study, the transcription and protein expression of seven genes of Infectious Laryngotracheitis virus (ILTV) were investigated: UL31 and UL37 possess homologues in all known Avian and mammalian herpesviruses, whereas UL46–UL49 and US4 are only conserved in most alphaherpesviruses. A peculiarity of the ILTV genome is the translocation of UL47 from the unique long region to a position upstream of US4 within the unique short region. Northern blot analyses revealed that all of the analysed genes were transcribed most abundantly during the late (γ) phase of replication, but the only true late (γ2) gene was UL47. Using monospecific rabbit antisera, the protein products of all of the genes could be detected and localized in ILTV-infected cells. Considerable amounts of the UL31, UL47 and UL48 gene products were found in the cell nuclei, whereas the other proteins were restricted largely to the cytoplasm. Like the respective tegument proteins of other herpesviruses, the UL37 and UL46–UL49 gene products of ILTV were incorporated into virus particles, whereas the UL31 protein and the glycoprotein encoded by US4 (gG) were not detectable in purified virions. It was also demonstrated that the UL48 protein of ILTV is able to activate an alphaherpesvirus immediate-early gene promoter, which is also a typical feature of other UL48 homologues. Taken together, these results indicate that the functions of all of the investigated ILTV proteins are related to those of their homologues in other alphaherpesviruses.
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Molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an economically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infection of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phenotype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been elucidated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suitable for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been identified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines.
Dorothee Helferich - One of the best experts on this subject based on the ideXlab platform.
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molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an econom- ically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infec- tion of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phe- notype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been eluci- dated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suit- able for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been iden- tified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines. Infectious Laryngotracheitis virus / DNA sequence / monoclonal antibodies / recombinant live- virus vaccines / viral vectors
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the ul47 gene of Avian Infectious Laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Jens Peter Teifke, Thomas C Mettenleiter, Walter FuchsAbstract:The genome of Infectious Laryngotracheitis virus (ILTV) exhibits several differences from those of other Avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3'-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.
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identification of transcripts and protein products of the ul31 ul37 ul46 ul47 ul48 ul49 and us4 gene homologues of Avian Infectious Laryngotracheitis virus
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Thomas C Mettenleiter, Walter FuchsAbstract:In the present study, the transcription and protein expression of seven genes of Infectious Laryngotracheitis virus (ILTV) were investigated: UL31 and UL37 possess homologues in all known Avian and mammalian herpesviruses, whereas UL46–UL49 and US4 are only conserved in most alphaherpesviruses. A peculiarity of the ILTV genome is the translocation of UL47 from the unique long region to a position upstream of US4 within the unique short region. Northern blot analyses revealed that all of the analysed genes were transcribed most abundantly during the late (γ) phase of replication, but the only true late (γ2) gene was UL47. Using monospecific rabbit antisera, the protein products of all of the genes could be detected and localized in ILTV-infected cells. Considerable amounts of the UL31, UL47 and UL48 gene products were found in the cell nuclei, whereas the other proteins were restricted largely to the cytoplasm. Like the respective tegument proteins of other herpesviruses, the UL37 and UL46–UL49 gene products of ILTV were incorporated into virus particles, whereas the UL31 protein and the glycoprotein encoded by US4 (gG) were not detectable in purified virions. It was also demonstrated that the UL48 protein of ILTV is able to activate an alphaherpesvirus immediate-early gene promoter, which is also a typical feature of other UL48 homologues. Taken together, these results indicate that the functions of all of the investigated ILTV proteins are related to those of their homologues in other alphaherpesviruses.
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Molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an economically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infection of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phenotype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been elucidated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suitable for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been identified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines.
Jutta Veits - One of the best experts on this subject based on the ideXlab platform.
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Identification and functional analysis of the small membrane-associated protein pUL11 of Avian Infectious Laryngotracheitis virus.
Virus research, 2011Co-Authors: Walter Fuchs, Jutta Veits, Harald Granzow, Thomas C MettenleiterAbstract:pUL11 is a highly conserved, small, acylated, membrane-associated tegument protein of herpesviruses. It is involved in final envelopment of nascent virions in the cytoplasm, although the precise mechanism is still unknown. By screening of mouse monoclonal antibodies (mAb) raised against purified particles of Infectious Laryngotracheitis virus (ILTV) of chickens (Veits et al., 2003a), we identified two mAb recognizing the 15 kDa UL11 protein (pUL11) of this Avian alphaherpesvirus. These mAb permitted detection and precise localization of pUL11 in mature ILT virions, as well as in the cytoplasm of infected chicken cells by Western blot analyses, indirect immunofluorescence tests, and immunoelectron microscopy. For investigation of gene function UL11-deleted ILTV recombinants were generated. Like its homologues in several other alphaherpesviruses, ILTV-pUL11 was shown to be nonessential for productive virus replication. However, compared to wild-type and UL11 rescued ILTV the deletion mutants exhibited significantly reduced virus yields and moderately impaired spread in cell culture. In the absence of pUL11, electron microscopy of infected cells revealed accumulations of tegument proteins with nucleocapsids, and marked distortions of Golgi membranes in the cytoplasm, which obviously inhibited the formation of mature, enveloped virus particles. Taken together, our results demonstrate that pUL11 is relevant for secondary envelopment of ILTV, and confirm functional conservation of this protein in herpesviruses. The now available unique pUL11-specific mAb will help to further analyze this function, which is presumably mediated by physical interactions with other viral gene products, in cultured cells and in the natural animal host of ILTV.
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molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an econom- ically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infec- tion of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phe- notype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been eluci- dated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suit- able for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been iden- tified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines. Infectious Laryngotracheitis virus / DNA sequence / monoclonal antibodies / recombinant live- virus vaccines / viral vectors
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the ul47 gene of Avian Infectious Laryngotracheitis virus is not essential for in vitro replication but is relevant for virulence in chickens
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Jens Peter Teifke, Thomas C Mettenleiter, Walter FuchsAbstract:The genome of Infectious Laryngotracheitis virus (ILTV) exhibits several differences from those of other Avian and mammalian alphaherpesviruses. One of them is the translocation of the conserved UL47 gene from the unique long (UL) to the unique short (US) genome region, where UL47 is inserted upstream of the US4 gene homologue. As in other alphaherpesviruses, UL47 encodes a major tegument protein of ILTV particles, whereas the US4 gene product is a non-structural glycoprotein, gG, which is secreted from infected cells. For functional characterization, an ILTV recombinant was isolated in which US4 together with the 3'-terminal part of UL47 was replaced by a reporter gene cassette encoding green fluorescent protein. From this virus, UL47 and US4 single-gene deletion mutants without foreign sequences were derived and virus revertants were also generated. In vitro studies revealed that both genes were non-essential for ILTV replication in cultured cells. Whereas US4-negative ILTV exhibited no detectable growth defects, maximum virus titres of the double deletion mutant and of UL47-negative ILTV were reduced about 10-fold compared with those of wild-type virus and rescued virus. Experimental infection of chickens demonstrated that UL47-negative ILTV was significantly attenuated in vivo and was shed in reduced amounts, whereas wild-type and rescued viruses caused severe disease and high mortality rates. As all immunized animals were protected against subsequent challenge infection with virulent ILTV, the UL47 deletion mutant might be suitable as a live-virus vaccine.
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identification of transcripts and protein products of the ul31 ul37 ul46 ul47 ul48 ul49 and us4 gene homologues of Avian Infectious Laryngotracheitis virus
Journal of General Virology, 2007Co-Authors: Dorothee Helferich, Jutta Veits, Thomas C Mettenleiter, Walter FuchsAbstract:In the present study, the transcription and protein expression of seven genes of Infectious Laryngotracheitis virus (ILTV) were investigated: UL31 and UL37 possess homologues in all known Avian and mammalian herpesviruses, whereas UL46–UL49 and US4 are only conserved in most alphaherpesviruses. A peculiarity of the ILTV genome is the translocation of UL47 from the unique long region to a position upstream of US4 within the unique short region. Northern blot analyses revealed that all of the analysed genes were transcribed most abundantly during the late (γ) phase of replication, but the only true late (γ2) gene was UL47. Using monospecific rabbit antisera, the protein products of all of the genes could be detected and localized in ILTV-infected cells. Considerable amounts of the UL31, UL47 and UL48 gene products were found in the cell nuclei, whereas the other proteins were restricted largely to the cytoplasm. Like the respective tegument proteins of other herpesviruses, the UL37 and UL46–UL49 gene products of ILTV were incorporated into virus particles, whereas the UL31 protein and the glycoprotein encoded by US4 (gG) were not detectable in purified virions. It was also demonstrated that the UL48 protein of ILTV is able to activate an alphaherpesvirus immediate-early gene promoter, which is also a typical feature of other UL48 homologues. Taken together, these results indicate that the functions of all of the investigated ILTV proteins are related to those of their homologues in other alphaherpesviruses.
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Molecular biology of Avian Infectious Laryngotracheitis virus
Veterinary Research, 2007Co-Authors: Walter Fuchs, Jutta Veits, Dorothee Helferich, Harald Granzow, Jens Peter Teifke, Thomas C MettenleiterAbstract:Infectious Laryngotracheitis virus (ILTV) is an alphaherpesvirus that causes an economically important chicken disease, which results in delayed growth, reduced egg production, and also frequently in death of the animals. After acute infection of the upper respiratory tract, the virus can establish latency in the central nervous system, and subsequent reactivations can lead to infection of naive chickens. For prevention of ILT, conventionally attenuated live vaccines are available. However, these vaccine strains are genetically not characterized, and reversions to a virulent phenotype occur. Although molecular analyses of ILTV are hampered by the lack of an optimal cell culture system, the complete nucleotide sequence of the ILTV genome has recently been elucidated, and several ILTV recombinants lacking nonessential, but virulence determining genes have been constructed. Animal trials indicated that genetically engineered stable gene deletion mutants are safe alternatives to the current vaccine strains. Furthermore, since live ILTV vaccines are suitable for fast and inexpensive mass administration, they are promising as vectors for immunogenic proteins of other chicken pathogens. Thus, immunization with ILTV recombinants expressing Avian influenza virus hemagglutinin was shown to protect chickens against ILT and fowl plague. Using monospecific antisera and monoclonal antibodies several virion proteins of ILTV have been identified and characterized. Since they include immunogenic envelope glycoproteins, these results can contribute to the improvement of virus diagnostics, and to the development of marker vaccines.
D B Boyle - One of the best experts on this subject based on the ideXlab platform.
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detection and quantitation of gallid herpesvirus 1 in Avian samples by 5 taq nuclease assay utilizing minor groove binder technology
Avian Pathology, 2010Co-Authors: B.g. Corney, Ibrahim S Diallo, A J De Jong, Glen Hewitson, M X Tolosa, B J Rodwell, S M Ossedryver, L I Pritchard, L.l. Wright, D B BoyleAbstract:A 5′ Taq nuclease assay utilizing Minor Groove Binder technology and targeting the thymidine kinase gene of gallid herpesvirus 1 (GaHV-1) was designed and optimized for use in diagnosing Avian Infectious Laryngotracheitis. The assay was specific for GaHV-1 in that it did not react with other Avian viral or bacterial pathogens. The detection limit was 1.0×10−2 median tissue culture Infectious dose per reaction or 90 target copies per reaction. Fifteen out of 41 diagnostic samples from sick birds reacted in the assay, five of which produced a typical alphaherpesvirus cytopathic effect (CPE) on chicken kidney (CK) cells. Sequencing, using amplicons generated by a polymerase chain reaction with primers flanking the 5′ Taq nuclease amplicon, confirmed the presence of GaHV-1 in six samples (two producing alphaherpesvirus CPE on CK cells, three not producing alphaherpesvirus CPE, and one that was not inoculated onto CK cells). Tracheal swabs taken from 18 healthy broilers did not react in the assay. The ability ...
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Detection and quantitation of gallid herpesvirus 1 in Avian samples by 5′ Taq nuclease assay utilizing Minor Groove Binder technology
Avian Pathology, 2010Co-Authors: B.g. Corney, Ibrahim S Diallo, A J De Jong, Glen Hewitson, M X Tolosa, B J Rodwell, S M Ossedryver, L I Pritchard, L.l. Wright, D B BoyleAbstract:A 5′ Taq nuclease assay utilizing Minor Groove Binder technology and targeting the thymidine kinase gene of gallid herpesvirus 1 (GaHV-1) was designed and optimized for use in diagnosing Avian Infectious Laryngotracheitis. The assay was specific for GaHV-1 in that it did not react with other Avian viral or bacterial pathogens. The detection limit was 1.0×10−2 median tissue culture Infectious dose per reaction or 90 target copies per reaction. Fifteen out of 41 diagnostic samples from sick birds reacted in the assay, five of which produced a typical alphaherpesvirus cytopathic effect (CPE) on chicken kidney (CK) cells. Sequencing, using amplicons generated by a polymerase chain reaction with primers flanking the 5′ Taq nuclease amplicon, confirmed the presence of GaHV-1 in six samples (two producing alphaherpesvirus CPE on CK cells, three not producing alphaherpesvirus CPE, and one that was not inoculated onto CK cells). Tracheal swabs taken from 18 healthy broilers did not react in the assay. The ability ...
