Ultra scale‐down studies of the effect of shear on cell quality; Processing of a human cell line for cancer vaccine therapy

Abstract

Whole cell therapy is showing potential in the clinic for the treatment of many chronic diseases. The translation of laboratory-scale methods for cell harvesting and formulation to commercial-scale manufacturing offers major bioprocessing challenges. This is especially the case when the cell properties determine the final product effectiveness. This study is focused on developing an ultra scale-down method for assessing the impact of the hydrodynamic environment on human cells that constitute the therapeutic product. Small volumes of a prostate cancer cell line, currently being developed in late phase II clinical trials as an allogeneic whole cell vaccine therapy for prostate cancer, were exposed to hydrodynamic shear rates similar to those present in downstream process, formulation and vial filling operations. A small scale rotating disc shear device (20 mL) was used over a range of disc speeds to expose cells to maximum shear rates ranging from 90 x 10(3) to 175 x 10(3) s(-1) (equivalent maximum power dissipation rates of 14 x 10(3) to 52 x 10(3) W kg(-1)). These cells were subsequently analyzed for critical cell quality attributes such as the retention of membrane integrity and cell surface marker profile and density. Three cell surface markers (CD9, CD147, and HLAA-C) were studied. The cell markers exhibited different levels of susceptibility to hydrodynamic shear but in all cases this was less than or equal to the loss of membrane integrity. It is evident that the marker, or combination or markers, which might provide the required immunogenic response, will be affected by hydrodynamic shear environment during bioprocessing, if the engineering environment is not controlled to within the limits tolerated by the cell components.