Identifying the Differentiation Program of Dendritic Cells

Immunity against invading pathogens is a complex process initiated by dendritic cells (DC). DCs originate in the bone marrow and finally reside in the draining lymphoid organs. As they migrate, DC acquire different functional abilities, which are represented by differences in expression of proteins on the cell surface. Dynamic changes in cell surface marker expression distinguish the stages of differentiation of DC. The objective of this study was to quantitatively describe the program of variation in cell surface proteins during DC differentiation.

DC precursors were removed from mouse bone marrow cells using magnetic bead separation. The precursors were then cultured with the growth factors GM-CSF and IL-4 for eight days. The expression of surface proteins on the cells was evaluated daily by multicolor flow cytometry.

We observed a linear increase over time in CD11c, a marker expressed on mature DCs, and a linear decrease in Gr-1, a marker expressed on immature DCs. The change in MHC class II expression, a marker for activated DCs, was non-linear. The data provide a basis for preliminary modeling of the differentiation program of DCs, which can ultimately be used to reverse-engineer the differentiation of DC precursors to prompt a specific immune response.