Submitted to: Great Lakes International Imaging and Flow Cytometry Association
Publication Type: Abstract only
Publication Acceptance Date: 10/22/2004
Publication Date: 10/22/2004
Citation: Bendfeldt, S., Pesch, B.A., Neill, J.D., Ridpath, J.F. 2004. Analysis of cell signaling pathways after infection with bovine viral diarrhea virus type 2 using flow cytometric techniques [abstract]. 13th Annual Meeting of the Great Lakes International Imaging and Flow Cytometry Association (GLIIFCA13). p. 17. Interpretive Summary:
Technical Abstract: Bovine viral diarrhea virus (BVDV), a pestivirus of the Flaviviridae family, is an economically important cattle pathogen with a world wide distribution. Based on their behavior in permissive epithelial cell cultures two different biotypes can be distinguished. While cells infected with a noncytopathic virus (ncp BVDV) do not show any morphological alterations, the cytopathic BVDV (cp BVDV) induces apoptosis. The effects of acute infection with BVDV may vary from clinically inapparent to clinically severe. One of the most serious forms of the disease is the severe acute BVD (saBVD) which is caused by virulent BVDV2 strains. These viruses cause disease syndromes affecting primarily the immune, respiratory, digestive systems. Currently nothing is known about determinants of virulence. Subclinical infections, as well as saBVD, lead to lymphoid depletion. Cell death observed in lymphoid cells does not appear to be mediated through an apoptotic-type mechanism. A more relevent cell culture model utilizing the bovine lymphosarcoma cell line BL3 was used to gain insight into the cell signaling pathways involved after infection with BVDV2. For that purpose, a variety of newly developed flow cytometric techniques was adapted for bovine cells infected with a cp BVDV2, a highly virulent ncp BVDV2 or a low virulent ncp BVDV2, respectively. Using the mitochondrial marker DePsipher**TM and CasPACE**TM, a marker for caspase activation, it was evident that infection with cp BVDV2 results in mitochondrial disruption and caspase activation and finally in apoptotic cell death as observed in cp BVDV1-infected cells. Furthermore, it was demonstrated that the infection of BL3 cells with cp BVDV2 as well as with the highly virulent ncp BVDV2 led to changes in overall tyrosine phosphorylation while the low virulent ncp BVDV2 did not show these phosphorylation changes. Another important signaling protein is the protein kinase Akt which plays a critical role in controlling the balance between cell survival and apoptosis. Its phosphorylation seems to be a key event only during infection with highly virulent ncp BVDV2. These results indicate that the infection with cp and ncp BVDV2 activates different signaling pathways and have an outcome different from that observed in cp BVDV2-infected cells.