Abstract
Background
Cord blood (CB) has been used as an alternative source of transplantable allogeneic stem cells for a variety of malignant and non-malignant diseases. However, we have demonstrated delayed recovery of T- and B-cell function, and T-cell subsets post unrelated CB transplantation (UCBT), and deficiencies of CB mononuclear cells (MNC) in producing cytokines, including G-CSF, GM-CSF, M-CSF, IL-12, and IL-15. In this study we have investigated the ex vivo generation of DC from CB versus mobilized adult peripheral blood (APB) for later use as adoptive cellular immonotherapy.
Methods
CB and APB-adherent MNC were cultured in serum-free media with GM-CSF, IL-4, FLT-3 ligand, tumor growth factor-β (TGF-β), and tumor necrosis factor-α (TNF-α) for 7 days. Morphology, phenotype, immunohistochemistry, clonogenic activity, and alloreactivity in MLR were evaluated.
Results
CB and APB monocyte-derived ex vivo expanded DC expressed similar DC markers CD83 (31.27±11.7% versus 34.0±5.2%, CB versus APB), CD1a (23.4±4.2% versus 27.6±6.3%), and CD80 (21.97±12.01% versus 27.7±5.95). Immunohistochemistry showed that cells with DC morphology expressed CD1a but not CD14. Neither FLT-3 ligand nor TGF-β enhanced DC expansion. Addition of 10% autologous plasma to CB cultures promoted greater cell survival and a 150% increase in CD1a+/CD80+ cell recovery. CB DC were 62% as effective stimulators of adult allogeneic T-cells as APB DC (p<0.05) in allogeneic MLR.
Discussion
While phenotypically similar, CB and APB DC have differential potency in allogeneic MLR, which may account for the difference in GvHD and infection incidence and severity between UCBT and allogeneic stem cell transplantation, and may require a different approach for adoptive cellular immunotherapy. The mechanism(s) associated with these differences require further elucidation.