Melanoma GVAX coordinately increases numbers of activated circulating monocytes and decreases circulating MDSCs. Flow cytometric analysis revealed significantly increased numbers (a) and activation (b) of circulating monocytes (CD14+ , CD11b+) 2 days following the first and fourth vaccinations. Monocyte activation was quantified as mean fluorescence intensity (MFI) of HLA-DR expression. Decreased percentages of myeloid-derived suppressor cells (CD14+ , CD11b+ , HLA-DR low or negative) among monocytes were observed at the same time intervals (c). Bars depict the mean ± SEM; p values from 2-sided Wilcoxon signed-rank test. MDSC myeloid derived suppressor cells, C treatment cycle, D treatment day.