Transcriptional targeting of B cells with viral vectors.

In order to optimize viral gene transfer into hematopoietic stem cells we developed retroviral and lentiviral vectors with B cell-specificity. Using fragments of the human CD19 promoter we demonstrate in mice that upon lethal irradiation and reconstitution with virus-treated bone marrow transgene expression is specific for the B cell-lineage. We compare various viral constructs with different promoter length and with or without B cell-specific enhancer regions in retro- and lentiviral backbones. Our data suggest that B cell-targeting for gene therapy approaches is feasible, leads to stable expression, and can be modulated by using different transduction and expression systems.