Generation of immature autologous clinical grade dendritic cells for vaccination of cancer patients

Background Dendritic cell (DC)-based vaccine is a promising approach for cancer therap y. Pioneer trials have been conducted using DC generated in research condit ions. There is now a need for generating DC in clinical grade conditions, i ncluding the use of closed systems, avoidance of FCS and respect of good ma nufacturing practices (GMP). Methods DC were generated from 84 leukapheresis products of 27 cancer patients enro lled in two Phase I/II trials of vaccination of either MAGE + tumors (n = 2 4) or prostate cancer (n = 3). Monocytes were seeded in culture bags in a s erum-free medium supplemented with IL-4 and GM-CSF. After a 7 day culture, DC were collected and most were pulsed with various MAGE-derived peptides. Results After a short leukapheresis (mean time: 66 min; mean processed blood: 5 L), a mean of 6 x 10(9) WBC were collected, from which 2.25% x 10(9) were seed ed. The culture procedure yielded a large number of DC (mean: 62 x 10(6) DC ) harboring the expected phenotype of immature DC (CD1a(+) CD14(-) HLA-DRCD80(+) CD86(+) CD83(-)). This phenotype was not altered by peptide loading . These DC, either fresh or thawed, were functionally effective in vitro. T heir s.c. and i.v. injections were devoid of any short-term side effect and associated with the induction of immune responses in the patients. Discussion Large numbers of functional immature clinical grade DC can be generated in a closed system from leukapheresis products in cancer patients. These resul ts provide the basis for large-scale studies of cancer immunotherapy under improved safety conditions.