Function of CD80 and CD86 on monocyte- and stem cell-derived dendritic cells.

Dendritic cells (DCs) consist of a heterogeneous population of hematopoietic cells characterized by their unique dendritic morphology, their efficient antigen-presenting capability to activate naïve CD4+ and CD8+ T cells, as well as their lack of lineage-specific markers. Functional properties comparing umbilical cord blood monocyte-derived and umbilical cord blood stem cell-derived DCs have not yet been investigated. Human umbilical cord blood CD14+ monocytes and CD34+ stem cells were induced to differentiate into dendritic cells using 100 ng/mL granulocyte-macrophage colony-stimulating factor (GM-CSF), 25 ng/mL interleukin (II)-4, 2.5 ng/mL tumor necrosis factor alpha (TNF-alpha) and 100 ng/mL GM-CSF, 25 ng/mL stem cell factor, and 2.5 ng/mL TNF-alpha, respectively. Differentiated dendritic cells were CD80+, CD86+, CD83+, CD54+, CD1a+, CD11b+, CD11c+, HLA-DR+, CD34-, CD3-, CD19-, CD14-, and CD16-. Reverse transcription polymerase chain reaction revealed that differentiating monocytes initially expressed CD86 mRNA while CD80 mRNA appeared on Day 2. Differentiating stem cells expressed both CD80 and CD86 mRNA on Day 2 of culture. Mixed lymphocyte reaction was employed to evaluate the two types of lineage-derived DCs. Monoclonal antibodies (mabs) to CD80 and CD86 were employed to assess their costimulatory roles. CD14 and CD34 derived DCs prior to the functional assay were stimulated for 18 h with 0.1 and 1.0 mg/mL Escherichia coli lipopolyssacharide, respectively. A decrease in stimulation as depicted by decreased T-cell activation was significant with mabs to both CD80 and CD86 on monocyte-derived DCs while only mabs to CD86 induced decreased T-cell activation by stem cell-derived DCs. The varied functional role of CD80 and CD86 costimulatory molecules is associated with DC differentiation from distinct cord blood-isolated hematopoietic lineages. These studies demonstrate that DC association with distinct hematopoietic lineages is of relevance in transplantation and vaccine therapies.