Adenoviral transduction of human 'clinical grade' immature dendritic cellsenhances costimulatory molecule expression and T-cell stimulatory capacity

The therapeutic use of dendritic cells (DC) in antigen-specific anti-tumor vaccines, requires sufficient numbers of functional DC, the preparation of which should comply with the code of Good Manufacturing Practice. In additi on, the expression of tumor specific antigen should be possible in these DC . As a preclinical step, the method reported here was developed in healthy volunteers. Monocytes (Mo) were isolated by leukapheresis from 12 donors, p urified by elutriation and then cultured for 6 days in sealed bags in AIM-V serum free medium with granulocyte-macrophage colony-stimulating factor (G M-CSF) and interleukin-13 (IL-13). Between 6x10(8) and 1x10(9) immature DC (iDC) could be differentiated from one leukapheresis. Cells displayed a cha racteristic iDC phenotype (CD1a(+), CD14(-), CD80(+), CD86(+), HLA DR+, CD8 3(-)), and had potent allogeneic and antigen dependent autologous T cell-st imulatory capacity. Moreover, iDC could be further differentiated into matu re DC by CD40 ligation as assessed by CD83 expression and the upregulation of HLA-DR and costimulatory molecules. After infection with a recombinant a denovirus encoding for beta-galactosidase (beta Gal), 50% to 80% of iDC exp ressed beta Gal without toxicity. Adenovirus infection increased the expres sion of both costimulatory molecules and CD83, and also increased allogenei c stimulatory capacity. Thus, the method developed here allows us to use la rge numbers of functional iDC as will be required for therapeutic uses in m an. These DC can express a transgenic protein. (C) 2000 Elsevier Science B. V. All rights reserved.