Characterization of cytotoxicity-related gene expression in response to virulent Marek's disease virus infection in the bursa of Fabricius.

Cell-mediated cytotoxic responses are critical for control of Marek's disease virus (MDV) infection and tumour development. However, the mechanisms of virus clearance mediated by cytotoxic responses in the bursa of Fabricius of chickens during MDV infection are not fully understood. In this study, the host cytotoxic responses during MDV infection in the bursa were investigated by examining the expression of genes in the cell lysis pathways. Partial up-regulation existed in the expression of the important cytolytic molecule granzyme A (GzmA), Fas, NK lysin and DNA repair enzyme Ape1, whereas little or no expression appeared in other cytolytic molecules, including perforin (PFN) and Fas ligand (FasL), and molecules involved in DNA repair and apoptosis in the bursa during MDV infection. These results suggest that less sustained cytotoxic activities are generated in the bursa of MDV-infected chickens. The findings of this study provide a more detailed insight into the host cytotoxic responses to MDV infection.