TEMs, like TAMs, are refractory to proinflammatory stimuli. In vitro stimulation of PMs, TEMs, and TAMs with Th1 (LPS + Ifng) and Th2 (Il4) cytokines, or the same cells left unstimulated (Ctrl). Top and bottom panels show the expression of Th1 (Nos2, Il12a) and Th2 (Arg1, Ccl17) responder genes, respectively. The expression of each gene is indicated as fold change (mean ± 2 × SD of 3 independent experiments) over its expression in unstimulated PMs (for PMs) or unstimulated TAMs (for TEMs and TAMs); endogenous control: β2m. Note that TEMs and TAMs are much less responsive than PMs to Th1 cytokine treatment. Conversely, Th2 cytokine stimulation elicits a greater response in TEMs and TAMs than in PMs.