Pervasive Differential Splicing in Marek's Disease Virus can Discriminate CVI-988 Vaccine Strain from RB-1B Very Virulent Strain in Chicken Embryonic Fibroblasts.

Yashar Sadigh,Paolo Ribeca,Venugopal Nair,Abdessamad Tahiri-Alaoui,Stephen Spatz

doi:10.3390/v12030329

Abstract

Marek’s disease is a major scourge challenging poultry health worldwide. It is caused by the highly contagious Marek’s disease virus (MDV), an alphaherpesvirus. Here, we showed that, similar to other members of its Herpesviridae family, MDV also presents a complex landscape of splicing events, most of which are uncharacterised and/or not annotated. Quite strikingly, and although the biological relevance of this fact is unknown, we found that a number of viral splicing isoforms are strain-specific, despite the close sequence similarity of the strains considered: very virulent RB-1B and vaccine CVI-988. We validated our findings by devising an assay that discriminated infections caused by the two strains in chicken embryonic fibroblasts on the basis of the presence of some RNA species. To our knowledge, this study is the first to accomplish such a result, emphasizing how relevant a comprehensive picture of the viral transcriptome is to fully understand viral pathogenesis.

Highlights

Marek’s disease (MD) is a major scourge of poultry, caused by Marek’s disease virus (MDV, known as Gallid herpesvirus-2, GaHV-2), a member of genus Mardivirus in the subfamilyAlphaherpesvirinae of the family Herpesviridae
Control of MD has been achieved by vaccination with the live attenuated GaHV-2 strain CVI-988 and the antigenically related non-oncogenic GaHV-3 vaccine strains such as SB-1, and Meleagrid herpesvirus 1 (Herpesvirus of turkey, HVT) strain Fc126 [1,2,3,4,5]
MDV strain CV-I988 was prepared from chicken embryo fibroblast (CEF) cells with two passage history after they were infected with Nobilis Rismavac vaccine virus

Summary

Introduction

Marek’s disease (MD) is a major scourge of poultry, caused by Marek’s disease virus (MDV, known as Gallid herpesvirus-2, GaHV-2), a member of genus Mardivirus in the subfamilyAlphaherpesvirinae of the family Herpesviridae. MD is characterised by paralysis, immunosuppression, and lymphoid infiltration into different tissues, including the peripheral nerves, eye, muscle, and skin. ( known as Rispens) and the antigenically related non-oncogenic GaHV-3 vaccine strains such as SB-1, and Meleagrid herpesvirus 1 (Herpesvirus of turkey, HVT) strain Fc126 [1,2,3,4,5]. These vaccines were introduced at different periods to control the disease caused by various MDV pathotypes.

Methods

Results

Conclusion