CD34+-derived CD11c+ + + BDCA-1+ + CD123+ + DC: expansion of a phenotypically undescribed myeloid DC1 population for use in adoptive immunotherapy.
BACKGROUND
DC are commonly defined as HLA-DR+/Lin- cells that can be CD11c+ + + CD123+/ -, termed DC1/myeloid DC that induce a Th1 response, or CD11c- CD123+ + +, termed DC2/lymphoid DC that induce a Th2 response. However, significant heterogeneity within DC preparations is apparent and supports the existence of several distinct DC subpopulations. This study aimed to expand and characterize CD34+ DC for use in immunotherapy.


METHODS
CD34+ cells were seeded at 1 x 10(5)/mL and expanded for 14 days in RPMI + 10% autologous plasma supplemented with GM-CSF, IL-4, Flt-3L and SCF. Maturation was induced with TNF-alpha and PGE2 for 2 days. DC were analyzed morphologically, phenotypically with a panel of MAb to lineage and DC markers, and functionally in MLR, T-cell assays and T-cell cytokine secretion by ELISA.


RESULTS
Significant cellular expansion was observed: 60+/-5 x 10(6) DC from 1 x 10(6) CD34+ cells (n=28). Phenotypically DC were characterized as HLA-DR+ +, CD11c+ + +, CD80+ +, CD83+, CD86+ +, CD123+ +, CD15+ +, CD33+ +, BDCA-1+ +, CD4+ and Lin-. DC displayed potent allostimulatory capacity and efficient presentation of KLH and tetanus toxin. DC-primed T cells secreted IFN-gamma (Th1); however, no detectable IL-4 (Th2) was noted.


CONCLUSIONS
We present features of CD34+ DC that have not been previously described. The CD34+ DC generated represent a population of myeloid DC functioning as DC1 but phenotypically expressing markers characteristic of both DC1 and DC2. This novel DC population is capable of inducing naive T-cell responses and can be expanded to clinically useful numbers. CD34+-derived DC represent attractive candidates for use in adoptive T-cell immunotherapy.
Ward
K A
KA
Bone Marrow Transplant Programme, Alfred Hospital, Melbourne, Australia.
Stewart
L A
LA
Schwarer
A P
AP
D015703:Antigens, CD / Q000378:metabolism*; D018952:Antigens, CD34 / Q000378:metabolism; D039521:CD11c Antigen / Q000378:metabolism*; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D006801:Humans; D016219:Immunotherapy, Adoptive; D053650:Interleukin-3 Receptor alpha Subunit; D016185:Receptors, Interleukin-3 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D015703:Antigens, CD; D018952:Antigens, CD34; D039521:CD11c Antigen; D016207:Cytokines; C115022:IL3RA protein, human; D053650:Interleukin-3 Receptor alpha Subunit; D016185:Receptors, Interleukin-3; D014409:Tumor Necrosis Factor-alpha; D015232:Dinoprostone