Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system

ABSTRACT Previous studies have demonstrated the safety and efficacy of a live-attenuated glycoprotein G (gG) deletion mutant vaccine strain of ILTV (∆gG-ILTV). In the current study, transcriptional profiles of chicken tracheal organ cultures (TOCs), 24 h post inoculation with ∆gG-ILTV or the gG-expr...

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Main Authors: Gayathri Gopakumar, Mauricio J.C. Coppo, Andrés Diaz-Méndez, Carol A. Hartley, Joanne M. Devlin
Format: Article
Language:English
Published: American Society for Microbiology 2025-02-01
Series:Microbiology Spectrum
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Online Access:https://journals.asm.org/doi/10.1128/spectrum.01183-24
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author Gayathri Gopakumar
Mauricio J.C. Coppo
Andrés Diaz-Méndez
Carol A. Hartley
Joanne M. Devlin
author_facet Gayathri Gopakumar
Mauricio J.C. Coppo
Andrés Diaz-Méndez
Carol A. Hartley
Joanne M. Devlin
author_sort Gayathri Gopakumar
collection DOAJ
description ABSTRACT Previous studies have demonstrated the safety and efficacy of a live-attenuated glycoprotein G (gG) deletion mutant vaccine strain of ILTV (∆gG-ILTV). In the current study, transcriptional profiles of chicken tracheal organ cultures (TOCs), 24 h post inoculation with ∆gG-ILTV or the gG-expressing parent wild-type strain, CSW-1 ILTV were explored and compared with the mock-infected TOCs using RNA-seq analysis. Transcriptomes of the vaccine and wild-type ILTV were also compared with each other. Although no viral genes (except for gG) were differentially regulated between the two ILTV-infected TOCs, pair-wise comparison of the transcriptomes of the ∆gG-ILTV or the CSW-1 ILTV-infected TOCs (each compared with mock-infected TOCs) identified the similarities and differences in host gene transcription between them. Several immune checkpoint inhibitors with likely roles in ILTV-mediated immune augmentation, and gene ontologies indicating cytokine response, and cytokine signaling were upregulated in both TOCs. Additionally, several other biological processes, molecular functions, and cellular components were enriched uniquely in the ∆gG-ILTV-infected TOCs, including those that indicated modifications to tracheal extracellular matrix (ECM) structural components, which may have a role in immune modulation in vivo. This study has revealed that the modifications of transcription of host genes during the early stages of ILTV infection are not limited to changes in cytokine or chemokine gene transcription, but several other immune-related genes and ECM components. Moreover, their differential regulation in the ex vivo system appears to be influenced by gG expression, potentially affecting the outcome of ILTV infection in vivo.IMPORTANCEInfectious laryngotracheitis virus (ILTV) remains a serious threat to poultry industries worldwide, causing significant economic losses. The glycoprotein G (gG) of ILTV is a virulence factor and a chemokine-binding protein with immunoregulatory functions. The influence of gG on the transcription of select host chemokine and cytokine genes has been demonstrated previously. This study extends our understanding of the early and localized host–ILTV interactions using genome-wide transcriptome analysis of ILTV-infected chicken tracheal organ cultures, and the role of gG during the process. Differential regulation of genes encoding immune checkpoint inhibitors observed in this study may have a role in ILTV-induced inhibition of type I interferon response, or negative regulation of T cell responses, bringing clarity to these ILTV immune-evasion mechanisms. Furthermore, differential regulation of genes encoding certain structural components and receptors with roles in cell migration, in the absence of gG, is consistent with the immunomodulatory role of ILTV gG.
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spelling doaj-art-d90b7faffb174860bc692c7c27cc74962025-02-04T14:03:41ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972025-02-0113210.1128/spectrum.01183-24Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo systemGayathri Gopakumar0Mauricio J.C. Coppo1Andrés Diaz-Méndez2Carol A. Hartley3Joanne M. Devlin4Asia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, AustraliaAsia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, AustraliaAsia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, AustraliaAsia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, AustraliaAsia-Pacific Centre for Animal Health, Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Victoria, AustraliaABSTRACT Previous studies have demonstrated the safety and efficacy of a live-attenuated glycoprotein G (gG) deletion mutant vaccine strain of ILTV (∆gG-ILTV). In the current study, transcriptional profiles of chicken tracheal organ cultures (TOCs), 24 h post inoculation with ∆gG-ILTV or the gG-expressing parent wild-type strain, CSW-1 ILTV were explored and compared with the mock-infected TOCs using RNA-seq analysis. Transcriptomes of the vaccine and wild-type ILTV were also compared with each other. Although no viral genes (except for gG) were differentially regulated between the two ILTV-infected TOCs, pair-wise comparison of the transcriptomes of the ∆gG-ILTV or the CSW-1 ILTV-infected TOCs (each compared with mock-infected TOCs) identified the similarities and differences in host gene transcription between them. Several immune checkpoint inhibitors with likely roles in ILTV-mediated immune augmentation, and gene ontologies indicating cytokine response, and cytokine signaling were upregulated in both TOCs. Additionally, several other biological processes, molecular functions, and cellular components were enriched uniquely in the ∆gG-ILTV-infected TOCs, including those that indicated modifications to tracheal extracellular matrix (ECM) structural components, which may have a role in immune modulation in vivo. This study has revealed that the modifications of transcription of host genes during the early stages of ILTV infection are not limited to changes in cytokine or chemokine gene transcription, but several other immune-related genes and ECM components. Moreover, their differential regulation in the ex vivo system appears to be influenced by gG expression, potentially affecting the outcome of ILTV infection in vivo.IMPORTANCEInfectious laryngotracheitis virus (ILTV) remains a serious threat to poultry industries worldwide, causing significant economic losses. The glycoprotein G (gG) of ILTV is a virulence factor and a chemokine-binding protein with immunoregulatory functions. The influence of gG on the transcription of select host chemokine and cytokine genes has been demonstrated previously. This study extends our understanding of the early and localized host–ILTV interactions using genome-wide transcriptome analysis of ILTV-infected chicken tracheal organ cultures, and the role of gG during the process. Differential regulation of genes encoding immune checkpoint inhibitors observed in this study may have a role in ILTV-induced inhibition of type I interferon response, or negative regulation of T cell responses, bringing clarity to these ILTV immune-evasion mechanisms. Furthermore, differential regulation of genes encoding certain structural components and receptors with roles in cell migration, in the absence of gG, is consistent with the immunomodulatory role of ILTV gG.https://journals.asm.org/doi/10.1128/spectrum.01183-24immune-evasionhost–virus interactionimmune responseinterferongene enrichmentavian alphaherpesvirus
spellingShingle Gayathri Gopakumar
Mauricio J.C. Coppo
Andrés Diaz-Méndez
Carol A. Hartley
Joanne M. Devlin
Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
Microbiology Spectrum
immune-evasion
host–virus interaction
immune response
interferon
gene enrichment
avian alphaherpesvirus
title Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
title_full Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
title_fullStr Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
title_full_unstemmed Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
title_short Host–virus interactions during infection with a wild-type ILTV strain or a glycoprotein G deletion mutant ILTV vaccine strain in an ex vivo system
title_sort host virus interactions during infection with a wild type iltv strain or a glycoprotein g deletion mutant iltv vaccine strain in an ex vivo system
topic immune-evasion
host–virus interaction
immune response
interferon
gene enrichment
avian alphaherpesvirus
url https://journals.asm.org/doi/10.1128/spectrum.01183-24
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