Background: Dendritic cells (DCs) play a critical role in the immune response and are a candidate for immunotherapy in cancer. Since gibbon ape leukemia virus (GALV) transduction of CD34+ cells is reasonably efficacious, we assessed the efficacy of GALV transduction of CD34+ derived DCs as a possible approach to creating genetically modified DCs for immunotherapy.
Methods: Peripheral blood CD34+ cells were transduced with retroviruses obtained from the PG13/LN C8 cell line, with the neomycin gene as a marker gene. After prestimulation of hematopoietic cells for 24 hours with 10 ng/mL interleukin (IL)-3, 10 ng/mL IL-6, 100 ng/mL stem cell factor, 100 ng/mL granulocyte-macrophage colony stimulating factor and 8 Amicrog/mL protamine sulfate, the cells were cultured in a transforming media prior to differentiating into DCs by GM-CSF, TNF-a and IL-4. Immunophenotyping analyses for confirmation of the generated DCs, colony formation assay and PCR were done for the expression of neomycin gene in the transduced cells.
Results: Titration of viral vectors indicated a transduction efficiency of 1×10(5) CFU/mL. Transduction efficiency for the CD34+ cells transformed to DCs was 45% and 38% before and after DC differentiation, respectively. Additionally, a mean (SEM) of 26.9% (11.4%) and 41.4% (11.8%) of the genetically modified DCs were positive for CD86+ HLA-DR and CD1a+CD14, respectively
Conclusion: This study showed that the majority of transduced CD34+ cells were successfully differentiated into cells identical to DCs according to morphology and immunophenotyping features, which could be a potential application in immunotherapy.