Comparison Between Magnetic Activated Cell Sorted Monocytes and Monocyte Adherence Techniques for in Vitro Generation of Immature Dendritic Cells: an Egyptian Trial

Introduction: Dendritic cells (DCs) are the most efficient antigen presenting cells, which are considered a central component of the immune system for their extraordinary capacity to initiate and modulate the immune responses elicited upon recognition of infectious agents. This has made them a major focus of interest in the conception of immunotherapeutic vaccine strategies.

Aim Of The Study: To standardise a protocol for in vitro differentiation of human peripheral blood monocytes into immature DCs (iDCs) upon treatment with specific growth factors and to compare two monocyte isolation methods including magnetic activated cell sorted (MACS) monocytes by CD14(+) immuno-magnetic beads and monocytes separated by adherence.

Material And Methods: Immature DCs were generated from monocytes of human peripheral blood in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4 after in vitro culture for seven days. Cultured cells were stained with surface markers of iDCs: FITC-anti-CD14, PE-anti-CD11c, PE-anti-CD1a, PE-Cy5-anti-HLA-DR, and PE-anti-CD83 for flow cytometry analysis.

Results: We found that the viability of MACS-DCs was higher than DCs derived from monocytes separated by adherence (median 50 and interquartile range 45-50 vs. 25 and 10-30, respectively; p < 0.001). Flow cytometry analysis revealed that the median interquartile percentages of MACS-DCs expressing CD14(-) was significantly higher compared to the DCs derived from monocytes separated by adherence (median 80.2 and interquartile range 77.7-80.7 vs. 40.2 and 30.4-40.6, respectively; p < 0.001). However, MACS-DCs expressed the same levels of CD11c, CD1a, and HLA-DR as well as CD83 compared to the DCs derived from monocytes separated by adherence with p value > 0.05.

Conclusions: Both positively selected monocytes and monocytes separated by adherence procedure gave the same results as regards cell surface marker expression, although the DCs purity and viability using MACS separated monocytes were better.