Proteomic analysis of the host response in the bursa of Fabricius of chickens infected with Marek's disease virus.

Marek's disease virus (MDV) is an oncogenic herpesvirus that causes a disease in chickens characterized by tumor formation and immunosuppression. In this paper, we identified differentially expressed proteins in the bursa of Fabricius of chickens infected with the highly virulent MDV strain RB1B, using two-dimensional gel electrophoresis on samples from time points coinciding with MDV life-cycle phases. By MALDI-TOF/TOF mass spectrometer, 26 proteins were identified, including 8 persistently up-regulated, four persistently down-regulated, 12 with fluctuating regulation, and 2 with significant differential expression but with no match in the published fowl databases. Database queries confirmed that these proteins were mainly associated with tumor biology, protein folding, signal transduction, immunology, cell proliferation and apoptosis. Interestingly, most stress and immune-associated proteins, such as apolipoprotein A-1, were significantly down-regulated, but tumor-associated proteins were significantly increased at 14 days post-infection (d.p.i), and at 21 d.p.i. These findings provide a basis for further studies to elucidate the role of these proteins in MDV-host interaction. This could lead to a better understanding of MDV infection mechanisms that cause immune suppression, and trigger tumor formation.