The allogeneic whole cell therapy field presents a novel challenge for cell line selection. Large numbers of candidates will he screened for desirable traits including cell growth rates and maintenance of critical product attributes. Screening cell lines for susceptibility to large scale processing conditions has become of increasing importance; innovators do not wish to face the quandary of clinically efficacious cell lines that show poor manufacturability. We have previously described an ultra scale-down method for assessing the impact of the hydrodynamic environment on human cells (McCoy et al., 2009). This body of work describes the validation of this experimental approach using a second, clinically tested, human prostate cancer cell line and describes an additional level of sub-population characterisation. The small-scale conditions set were similar to those expected in downstream process, formulation and vial filling operations with maximum shear rates ranging from 30 x 10(3) to 90 x 10(3) s(-1)(equivalent maximum power dissipation rates of 1.5 x 10(3) to 14 x 10(3) W kg(-1)). Changes to critical cell quality attributes such as membrane integrity retention, cell surface marker staining levels (CD9, CD59, CD147) and cell surface marker density is described. Evaluation of two sub-populations which are formed in response to shear showed distinct staining profiles. Identification of these phenotypically distinct populations, derived in response to the same hydrodynamic environment, poses an interesting bio-processing challenge with regards to both maintenance of product quality, but also highlights the potential benefit of process manipulation through shear-rate intervention with regards to product efficacy.