Vaccine by Chicken Line Interaction Alters the Protective Efficacy against Challenge with a Very Virulent plus Strain of Marek’s Disease Virus in White Leghorn Chickens

Shuang Chang,John R Dunn,Lucy F Lee,Jiuzhou Song,Mohammad Heidari,Huanmin Zhang,Catherine W Ernst

doi:10.4236/wjv.2012.21001

Abstract

Marek’s disease (MD) is a lymphoproliferative disease of domestic chickens caused by Marek’s disease virus (MDV), an oncogenic and highly contagious α-herpesvirus. MD has been controlled by vaccination but sporadic outbreaks of MD still occur in some parts of the world. Efforts to improve vaccine efficacy have continued in both research communities and vaccine industries. We reported the host genetic variation affecting Marek’s disease vaccine-induced immunity in chickens earlier. In this study, we evaluated chicken lines, vaccines, and line by vaccine interaction on the protective efficacy of vaccination against MD. Specific pathogen free chickens from the relatively resistant line 63 and the highly susceptible line 72 were primarily used to evaluate the protection by three kinds of vaccines (rMd5ΔMeq, CVI988/Rispens, and HVT) upon challenge with a very virulent plus strain of MDV, vv+648A. Our data confirmed that both the chicken line and the vaccine significantly affected the protective efficacy of vaccination and showed that a chicken line by vaccine interaction, in most of the trials, also altered vaccine protective efficacy. More interestingly, although the protective index of all vaccine strains was higher in resistant than in susceptible line of chickens, the difference for HVT protection was striking and warrants further study. The findings may have important implications for vaccine development as well as for selective use of particular vaccines in specific lines of chickens to achieve maximum protection at minimized costs.

Highlights

Marek’s disease (MD) is an acute viral neoplastic disease in chickens, caused by a cell-associated α-herpesvirus of the genus Mardivirus, commonly referred to as Marek’s disease virus (MDV)
We reported the host genetic variation affecting Marek’s disease vaccine-induced immunity in chickens earlier
We evaluated chicken lines, vaccines, and line by vaccine interaction on the protective efficacy of vaccination against MD

Summary

Introduction

Marek’s disease (MD) is an acute viral neoplastic disease in chickens, caused by a cell-associated α-herpesvirus of the genus Mardivirus, commonly referred to as Marek’s disease virus (MDV). MD is characterized by the presence of T cell lymphoma as well as infiltration of nerves and organs by lymphocytes [1]. There are three serotypes of MDV based on their antigenic differences and pathogenicity. Serotype 1 is an oncogenic and pathogenic virus causing MD in susceptible chickens. Serotypes 2 (e.g. SB-1) and 3 (turkey herpesvirus, HVT) are apathogenic [2,3]. MD remains a significant problem for the poultry industry throughout the world due to losses from con-

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