Consistent and high rates of gene transfer can be obtained using flow-through transduction over a wide range of retroviral titers.

Flow-through transduction methods have been developed to overcome physical limitations imposed by Brownian motion on retroviral delivery. This method uses net fluid flow of retroviral supernatants through a porous membrane on which the target cells are placed. It is shown that in comparison to static transduction methods, flow-through transductions have the following advantages: (i) flow-through transductions lead to transduction rates that exceed those obtained by static transduction; (ii) flow-through transductions lead to high transduction rates even at low viral concentrations, eliminating many of the concerns associated with the production of high-titer virus supernatants; (iii) flow-through transductions are insensitive to viral titers, eliminating the need to produce consistently retroviral supernatants at given virus concentrations; (iv) flow-through transductions can be carried out without the use of polycations, such as polybrene; and (v) the volume of viral supernatants needed for gene transfer can be sharply reduced. Taken together, these advantages of flow-through transductions are likely to lead to their widespread use for gene transfer work, both in research and clinical settings.