This proposal seeks to provide a solution to a major obstacle in commercial scale operations of mammalian cell bioreactors, i.e. shear stress-induced cell detachment. Specific objectives of the proposal are to: - Determine the role of an adhesive glycoprotein (von Willebrand factor(vWF)) in the resistance to shear stress-induced detachment of anchorage-dependent mammalian cells. - Determine if and how shear stress itself may enhance such resistance to detachment. By using a previously developed flow apparatus for subjecting cells to shear, the PI proposes to determine the critical shear stress for cell detachment. To test the hypothesis that secretion of vWF increases resistance to detachment, the PI will compare the critical shear stress for detachment of genetically engineered Chinese Hamster Ovary (CHO) cells that express vWF to wild-type CHO cells which do not express vWF. To address the second objective, the PI proposes to investigate if shear stress stimulates the synthesis of vWF and another glycoprotein, fibronectrin. The production and secretion of these glycoproteins is to be measured using quantitative immunofluorescence. The PI is considered to be well qualified to carry out the proposed research and I recommend funding of this proposal.
