PURE POPULATIONS OF TRANSDUCED PRIMARY HUMAN-CELLS CAN BE PRODUCED USING GFP EXPRESSING HERPES-VIRUS VECTORS AND FLOW-CYTOMETRY

Herpes simplex virus (HSV) has often been suggested as a vector for ge ne delivery to the nervous system although it is also capable of infec ting many other cell types. HSV alsb has the ability to package large genetic insertions so the expression of multiple genes from a single v irus is possible. Here we show that a green fluorescent protein (GFP) expressing HSV1 vector can transduce two primary human cell types -qui escent human CD34(+) hematopoietic progenitor cells and dendritic cell s - which are both hard to transduce by other means. We also show that GFP is an effective marker when expressed from an HSV vector in vivo in the mouse brain. When GFP is expressed together with a second gene (in this case lacZ) from a single virus, transduced GFP-positive CD34- hematopoietic progenitor cells or dendritic cells can both be generate d at an effective efficiency of 100% for the second gene. Here transdu ction with the vector is combined with flow cytometry allowing GFP-pos itive cells to be sorted from the untransduced population. Such comple tely transduced populations of quiescent CD34(+) hematopoietic progeni tor and dendritic cells cannot easily be achieved by other means, and might thus allow experimental or therapeutic protocols to be carried o ut requiring high-level transduction which would not otherwise be poss ible. Such an approach using HSV vectors might also be applicable to o ther cell types for which transduction is as yet unreliable or of low efficiency.