Hierarchical clustering of differentially expressed genes and the representative GO categories associated with the genes most highly expressed by each monocyte subset. (A) Hierarchical clustering using city block distance and average linkage of the 1554 differentially expressed genes (P < .05, fold change ≥ 1.5) reveals 6 distinct clusters. Clusters I and II are composed of 862 genes most highly expressed by the classical subset, clusters III and IV with 135 genes most highly expressed by the intermediate subset, and clusters V and VI with 557 genes most highly expressed by the nonclassical subset. The relative log2 fold change for each gene is shown by the corresponding heat maps. The most highly expressed genes from each subset were analyzed for enrichment of categories in Gene Ontology biologic processes using DAVID tools. Representative categories and associated genes enriched for the (B) classical, (C) intermediate, and (D) nonclassical subset are shown. The log2 levels of associated genes normalized to the intermediate subset are shown and listed according to decreasing MFI for the classical monocyte subset. C indicates classical monocyte subset: I, intermediate monocyte subset; and N, nonclassical monocyte subset.
