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News Article

New study identifies immune cells which increase susceptibility to Marek’s disease in chickens

Scientists at the Pirbright Institute, UK, have demonstrated that suppressor lymphocytes,  chicken TGF-beta+ Treg cells, are involved in pathogenesis and immunosuppression of Marek’s disease virus infection.

Marek’s disease virus (MDV) is highly contagious and causes a deadly cancer of the lymph nodes (lymphoma) and immunosuppression in poultry, making birds susceptible to secondary infections. MDV is a major threat to the poultry industry, with losses relating to the disease estimated to be up to $2 billion worldwide.

The research carried out at the Pirbright Institute and published in PLOS Pathogens, reveals that infection with Marek’s disease virus increases the number of new immune cells, called suppressor lymphocytes, which suppress the chicken immune response.

Treg cells are crucial for the maintenance of tolerance and control of immune responses, especially during viral infection and tumour formation. MDV infection causes immunosuppression and induces transformation of CD4+ T cells in chicken.  The study demonstrated that a population of chicken CD4+ T cells express inhibitory molecules including TGF-beta and have immune-regulatory properties. TGF-beta+ Treg cells were detected in different chicken lymphoid tissues. The study also shows that higher numbers of suppressor lymphocytes increase the susceptibility of chickens to lymphoma formation.

According to Dr Shahriar Behboudi, Head of the Avian Immunology Group at Pirbright Institute, “some viruses exploit host immune cells for their own purpose to evade normal host defences. We found that MDV can modulate immune responses by activating suppressor lymphocytes, contributing to immunosuppression and lymphoma formation.”

The scientists also noted that lymphoma cells have similar characteristics to suppressor lymphocytes, meaning they too can suppress immune responses. Combined, these findings identify new pathways that are involved in the development of the disease, which can help identify chicken lines that are more resistant to MDV.

This study was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) grant number BBS/N002598/

1. Citation: Gurung A, Kamble N, Kaufer B B, Pathan A, Behboudi S (2017). Association of Marek’s Disease induced immunosuppression with activation of a novel regulatory T cells in chickens. PLoS Pathogens, 13(12):e1006745.


Contact: Dr S. Behboudi, the Pirbright Institute, Ash Road, Woking, United Kingdom. Email:;