Autocrine Interferon Priming in Macrophages but Not Dendritic Cells Results in Enhanced Cytokine and Chemokine Production after Coronavirus Infection

Zhou, Haixia; Zhao, Jincun; Perlman, Stanley

Finally, we measured CXCL10 protein levels by an ELISA and, as expected, observed increased production of CXCL10 in infected cells. However, CXCL10 protein levels in MHV-infected BMM were comparable to those in IFN-treated mock-infected cells, even though mRNA amounts in MHV-infected cells were appreciably higher at 16 h p.i. (compare Fig. 6D with Fig. 7A ). IFN treatment of MHVinfected BMM, BMDC, and 17Cl-1 cells did not increase CXCL10 protein production compared to IFN treatment alone. These results likely reflect MHV-induced inhibition of host cell protein synthesis, mediated in part by nsp1 (11, 14, 34, 35) . Of note, expression of the MyD88-dependent molecule TNF was not upregulated by IFN treatment in mock-infected or MHV-infected cells (Fig. 7B) , consistent with the real-time qPCR data shown in Fig. 6E .