ALV-J infection induces chicken monocyte death accompanied with the production of IL-1β and IL-18.

Manman Dai,Ming Liao,Min Feng,Meiqing Shi,Tingting Xie,Xiquan Zhang,Yuanfang Li,Zhuohao Ruan

doi:10.18632/oncotarget.21906

Abstract

Immunosuppression induced by avian leukosis virus subgroup J (ALV-J) causes serious reproduction problems and secondary infections in chickens. Given that monocytes are important precursors of immune cells including macrophages and dendritic cells, we investigated the fate of chicken monocytes after ALV-J infection. Our results indicated that most monocytes infected with ALV-J including field or laboratory strains could not successfully differentiate into macrophages due to cells death. And cells death was dependent upon viral titer and accompanied with increased IL-1β and IL-18 mRNA levels. In addition, ALV-J infection up-regulated caspase-1 and caspase-3 activity in monocytes. Collectively, we found that ALV-J could cause cell death in chicken monocytes, especially pyroptosis, which may be a significant reason for ALV-J induced immunosuppression.

Highlights

Avian leukosis virus (ALV) is a chicken retrovirus that induces neoplastic disease and immunosuppression, and is an important factor in avian viral coinfections [1,2,3]
Western blot analysis confirmed the expression of ALV subgroup J (ALV-J) envelope protein in monocytes isolated from chickens S1 and S2, which was negative in monocytes from chicken N1 and N2 (Figure 1B)
We demonstrated that ALV-J infection induces chicken monocytes death, and the forms of cell death are most likely to be pyroptosis

Summary

Introduction

Avian leukosis virus (ALV) is a chicken retrovirus that induces neoplastic disease and immunosuppression, and is an important factor in avian viral coinfections [1,2,3]. ALV subgroup J (ALV-J) infections greatly enhance the probability of a secondary infection through virally-induced immunosuppression. Our previous studies demonstrated that ALV-J induces host innate immune responses in chicken’s primary monocytederived macrophages suggesting that macrophages are important in ALV-J associated immune defense and escape [4]. ALV-J infection inhibits differentiation and maturation of chicken bone marrow-derived dendritic cells (BM-DC) and triggers their apoptosis [5, 6]. Monocytes are circulating precursors of tissue DCs and macrophages [7].

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