Dendritic cells (DC) are professional antigen-presenting cells that are pro
mising adjuvants for clinical immunotherapy. Methods to generate in vitro l
arge numbers of functional human DC using either peripheral blood monocytes
or CD34(+) pluripotent hematopoietic progenitor cells have been now develo
ped. For this purpose, their in vitro production for further clinical use n
eed to fit good manufacturing practice (GMP) conditions. In the present rev
iew, we give our experience of such a procedure: it includes collection of
mononuclear cells by apheresis, separation of monocytes by elutriation, and
culture of monocytes with GM-CSF + IL-13 + human serum (autologous patient
's serum or AB serum) or in a serum-free medium (AIM V). The characteristic
s of monocyte-derived DC grown in these various conditions varied mainly re
garding their phenotype and their morphology in confocal microscopy, wherea
s no significant differences were found in their capacity to phagocytize la
tex particles and to stimulate allogeneic (MLR) or autologous lymphocytes (
antigen-presentation tests). The DC were also cryopreserved in bags (either
by putting the bags directly in a -80 degreesC mechanical freezer or using
a classical liquid nitrogen controlled-rate freezer at -1 degreesC/min) in
a solution containing 10% dimethyl sulfoxide (Me2SO) and 2% human albumin
in doses of DC available for several infusions. The mean recoveries after f
reezing and thawing were not statistically different (around 70%). The immu
nophenotype of DC, as well as the T lymphocyte-stimulating capacity, were n
ot modified by the freezing-thawing procedure. The results obtained demonst
rate that the experimental conditions we set up are easily applicable in cl
inical trials and lead to large numbers of well-defined DC. Clinical trials
using DC already published will be discussed.