Expression of the nlsLacz gene in dendritic cells derived from retrovirally transduced peripheral blood CD34+ cells.

Background And Objective: Gene transfer and expression of exogenous genetic information coding for an immunogenic protein in antigen presenting cells (APCs) can promote an immune response. This was investigated by retroviral transfer of a marker gene into CD34+ derived APCs.

Design And Methods: To achieve long term expression of a specific transgene in APCs, G-CSF mobilized peripheral blood CD34+ cell populations were retrovirally transduced with the bacterial nlsLacZ, a marker gene used here as a model, in the presence of IL-3, IL-6, GM-CSF and SCF prior to being induced to differentiate into dendritic and macrophage cells by GM-CSF and TNF-a.

Results: Addition of IL-4 was found to induce dendritic differentiation preferentially by inhibiting proliferation and differentiation of the macrophage lineage. As assessed by X-Gal staining, LacZ gene expression was observed in cells from both the dendritic lineage (CD1a+/CD14-) which still exhibits the highest immunostimulatory activity in mixed lymphocyte reaction and from the macrophage lineage (CD1a-/ CD14+).

Interpretation And Conclusions: This study sets out the possibility of transducing dendritic and macrophage progenitors present in the CD34+ cell population and in using a marker gene such as nlsLacZ to study gene expression in antigen presenting cell compartments.