Photoactivatable retroviral vectors: a strategy for targeted gene delivery.

We have explored a novel strategy for the targeting of retroviral vectors to particular sites or cell types. This strategy involves a method whereby the infectivity of a retroviral vector is neutralized by treatment of viral particles with a photocleavable, biotinylation reagent. These modified viral vectors possess little to no infectivity for target cells. Exposure of these modified viral vectors to long-wavelength UV light induces a reversal of the neutralizing, chemical modification resulting in restoration of infectivity to the viral vector. This infectivity 'trigger' possesses great potential, both as a research tool and as a novel tactic for the targeting of gene-transfer agents, since it would become possible to direct both the time and location of a viral infection in a versatile manner.