Fig 4.

Viral IL-10 expressed during productive HCMV infection polarizes bystander monocytes toward an alternatively activated M2c phenotype. CD14⁺ monocytes were cultured for 24 h in conditioned supernatants from HFF cultures productively infected with a viral IL-10 deletion virus (vIL-10 del) or parental virus (Parent) or mock infected (Mock) for 24 h. (A) Representative flow cytometry histograms of cells expressing CD14, CD163, and HLA-DR. Open histograms show expression in monocytes cultured with conditioned supernatants from vIL-10 del-infected and parent virus-infected (both in the AD169 backbone) samples compared to filled histograms that show expression in monocytes incubated with conditioned supernatants from mock-infected samples. (B and C) Graphs depicting the mean fluorescence intensity (MFI) fold change of CD14, CD163, and HLA-DR in monocytes cultured with conditioned supernatants from vIL-10 del- and parent virus-infected samples, as indicated (relative to monocytes incubated with conditioned supernatants from mock-infected samples). The number of independent biological replicate experiments (n) is shown. Error bars indicate the standard errors of the means. Significant differences between samples compared to mock infection were determined using a one-tailed, paired Student t test: *, P < 0.05; **, P < 0.01; ***, P < 0.001.