Dendritic cells (DCs) are potent antigen-presenting cells that can act
ivate quiescent T lymphocytes. When pulsed with tumor-associated antig
en (TAA) peptide or protein, murine DCs can provide antitumor immunity
. me reasoned that DCs retrovirally transduced with TAA genes might ha
ve important advantages over peptide- or protein-pulsed DCs, including
long-term TAA presentation in pipe, and presentation of important but
undefined epitopes. Therefore, we attempted to retrovirally transduce
human DCs with a melanoma TAA gene (MART-1) and determine whether the
se transduced DCs could raise a specific antitumor response from quies
cent autologous T lymphocytes. After retroviral transduction, human CD
34(+) cells were differentiated into DCs in vitro using granulocyte ma
crophage colony-stimulating factor, tumor necrosis factor alpha, and s
tem cell factor, This method consistently yielded a population of DCs
as analyzed by morphology phenotype, and MLR. Flow cytometric analysis
revealed that 22-28% of cells expressing the DC phenotype also expres
sed a transduced marker gene. When DCs were transduced with the gene e
ncoding MART-1, they stimulated much higher levels of cytokine release
by MART-1-specific tumor-infiltrating lymphocytes than control DCs tr
ansduced with an irrelevant gene. In vitro stimulation using MART-1-tr
ansduced DCs but not control-transduced DCs raised specific antitumor
CTLs from autologous quiescent T cells. These results provide evidence
that human DCs can be retrovirally transduced with a TAA gene and tha
t these transduced cells can raise a specific antitumor immune respons
e in vitro, Transduced DCs may be useful for in vivo immunization agai
nst TAA.