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Cytotherapy. 2009;11(8):1084-9. doi: 10.3109/14653240903271230.

Indoleamine-2,3-dioxygenase enzyme expression and activity in polarized dendritic cells.

Author information

1
Medical Oncology Immunotherapy Group, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire 03756, USA.

Abstract

BACKGROUND AIMS:

Polarized mature dendritic cells (DC) can activate cytolytic T-lymphocyte (CTL) responses and may be a more effective clinical strategy in DC-based cancer vaccines. A subset of mature DC can down-regulate the T-cell immune response through expression of indoleamine-2,3-dioxygenase (IDO). We determined whether polarizing DC ex vivo increased IDO expression and activity.

METHODS:

Peripheral blood monocytes from healthy volunteers were cultured ex vivo in polarizing and non-polarizing culture conditions. DC IDO expression was detected by Western blot. IDO enzyme activity was determined by high-performance liquid chromatography (HPLC) measurement of kynurenine (K) and tryptophan (T) concentrations in culture supernatants.

RESULTS:

IDO protein was markedly increased in DC after polarization (median 1222.4%, range 331.5-2113.3%) versus non-polarized DC (median 28.3%, range 3.7-119.8%; P=0.04). The median K/T ratio was significantly higher in polarized DC versus non-polarized DC (6.34, range 6.02-6.65, versus 0.047, range 0.004-0.541; P=0.04). IDO protein expression correlated with enzyme activity (r=0.80, P=0.002).

CONCLUSIONS:

DC polarizing culture conditions increased expression of IDO protein and IDO enzyme activity. DC culture and maturation methodologies may impact the effectiveness of adoptive DC therapy.

PMID:
19929471
PMCID:
PMC3786593
DOI:
10.3109/14653240903271230
[Indexed for MEDLINE]
Free PMC Article

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