Improved retroviral transduction of hematopoietic progenitors by combiningmethods to enhance virus-cell interaction

One of the factors required for successful retroviral transduction Is conta ct between viral particles and target cells. We hypothesized that combining agents that improve virus-target cell interaction via different mechanisms will increase transduction efficiency. We examined the transduction effici ency of leukemic K562 cells, primary normal and chronic myelogenous leukemi a CD34(+) cells with the amphotropic retroviral vector, G1Na, packaged in P A317 by enumerating G418-resistant colonies in semisolid media. We evaluate d the ability of the recombinant fibronectin fragment, CH296, cationic lipi ds, or a transwell flow-through system, alone or in combination to improve retroviral transduction. Transduction of K562 cells improved 1.5 to two-fol d with lipids or CH296, while their combination improved transduction 2.5-f old. Transduction of K562 cells in the transwell flow-through system improv ed transduction three-fold. Transduction of normal (NL) CD34(+) CFC improve d 10-fold with lipids and 20-fold with CH296. Lipid and CH296 had synergist ic effects. The transwell flow-through system improved transduction of norm al CD34(+) CFC 30-fold. Finally, similar to what was seen for K562 cells, t ransduction of CML CFC improved two- to three-fold with either CH296 or lip ids, whereas the combination had synergistic effects. We conclude that any physical means that enhances contact between viral particles and target cel ls improves transduction. Two such methods that have different action mecha nisms have additive or synergistic effects on transduction.