Figure 3

P. pastoris- produced mGM-CSF is biologically active. Mouse bone marrow cells were differentiated into DCs using either E. coli- (black bars) or P. pastoris-produced (grey bars) mGM-CSF. Six surface maturation markers were measured by flow cytometry on non-infected ('none') or M. bovis BCG-infected BM-DCs ('M. bovis'), which were also CD11c+. Both mGM-CSF preparations were equally potent in differentiating bone marrow cells into BM-DCs (similar expression of cell surface markers). The latter also responded similarly to a stimulus, i.e., infection with M. bovis BCG, regardless of the source of mGM-CSF used for differentiation. The percentage of obtained CD11c+ cells was also very similar for both mGM-CSF sources (almost 100%; data not shown). This demonstrates that, based on cell surface marker expression and reaction to M. bovis BCG infection, both sources of mGM-CSF produced phenotypically indistinguishable BM-DCs.