Effect of cell lysates on retroviral transduction efficiency of cells in suspension culture

Recombinant retroviruses are effective vectors able to integrate transgenes into the target cell's genome to achieve longer-term expression. This study investigates the effect of cell lysis products, a common cell culture by-product, on the transduction of suspension cells by gammaretroviral vectors. Cell lysates derived from human and murine suspension cell lines significantly increased the transduction of human TF-1 and K-562 cell lines by gibbon ape leukemia virus-pseudotyped retroviral vectors without altering tropism. The transduction efficiency of TF-1 cells increased as a function of lysate concentration and decreased with increasing target cell concentrations. This was adequately predicted using a saturation equation based on the lysed-to-target cell concentration ratio, R, where: Lysate completely masked the effects of fibronectin when the two were added in combination. With protamine sulfate, the transduction efficiency was increased by lysate to 58% from 20% for protamine sulfate alone. Overall, the presence of cell lysate significantly influenced the outcome of the transduction process, either alone or in the presence of protamine sulfate or fibronectin. Biotechnol. Bioeng. 2010;105: 1168–1177. © 2009 Wiley Periodicals, Inc.