Genome-Wide Gene Expression Analysis Identifies the Proto-oncogene Tyrosine-Protein Kinase Src as a Crucial Virulence Determinant of Infectious Laryngotracheitis Virus in Chicken Cells

Li, Hai; Wang, Fengjie; Han, Zongxi; Gao, Qi; Li, Huixin; Shao, Yuhao; Sun, Nana; Liu, Shengwang

Next, to determine whether the effects of the Src oncogene on ILTV infection that we observed in the chicken hepatoma cell line LMH could also be observed in normal liver cells, an in ovo examination of embryo livers was conducted. Histopathological examinations of slides with liver tissue stained with H&E revealed the infiltration of lymphocytes in all inoculated embryos (data not shown). However, different levels of hepatic tissue damage were observed among the inoculated embryos upon the administration of serially increasing dosages of SU6656. In embryos inoculated only with ILTV, necrosis was absent in four of the six samples, and mild necrosis was observed in the other two (Fig. 4D) , while hepatic tissue necrosis occurred in most of the inoculated embryos upon coinoculation with SU6656 (with 25 g of SU6656, tissue necrosis was absent in three embryos, mild in one embryo, moderate in one embryo, and severe in one embryo; with 50 g of SU6656, tissue necrosis was absent in two embryos, mild in one embryo, moderate in one embryo, and severe in two embryos; with 250 g of SU6656, tissue necrosis was moderate two embryos and severe in four embryos) (Fig. 4D) . No necrosis was observed in the livers of either control embryos or embryos that were inoculated only with 250 g of SU6656 (Fig. 4D) . Consistent with the findings in LMH cells (Fig. 3F and G) , embryo allantoic fluids (Fig. 4B) , and CAMs (Fig. 4C) , a dose-dependent reduction of virus replication by SU6656 was also observed in inoculated embryos, as assayed by qPCR (Fig. 4E) .