Transcriptional profiling of Drosophila S2 cells in early response to Drosophila C virus

BACKGROUND: The innate immune response like phagocytosis, encapsulation and antimicrobial peptide (AMP) production often occur in the early stage of host-pathogen interactions in Drosophila melanogaster. To investigate the Drosophila early immune response to Drosophila C virus, we characterized the DCV infection-response transcriptome of Drosophila Schneider 2 (S2) cells at one hour post inoculation. METHOD: The total RNA was extracted from treated S2 cells by using Trizol reagent and then analyzed by CapitalBio Corp for Drosophila GeneChip (Affymetrix) assay. Then the results of signaling pathway and protein interaction about these genes were analyzed by MAS 3.0 software. RESULTS: Most significantly affected genes (656 genes) by DCV infection were regulated as the same way in inactivated DCV treatment, but inactivated white spot syndrome virus (WSSV) showed a different transcriptome. DCV infection up-regulated the expression levels of 275 genes and down-regulated that of 442 genes significantly and some affected genes were related to phagocytosis. DCV infection activated the JAK/STAT pathway by 1 hour post incubation. The Imd pathway was activated and transcriptional induction of antimicrobial peptides (AMPs) from this pathway was enhanced by 1 hour post incubation. But the Toll pathway was not activated like Imd pathway and the expression levels of AMPs from this pathway was reduced. In addition, most pattern-recognition receptors were inhibited and the antiviral RNAi pathway was not activated in the early stage of DCV infection. CONCLUSIONS: In conclusion, the present study demonstrates that DCV infection may activate phagocytosis, JAK/STAT pathway and Imd pathway in the early host-virus interactions. These results indicate that DCV is capable of activating or inhibiting some immune responses in the host cells and these changes would be vital for virus entry and replication.