Fig. 5: Dysregulation of antigen presentation and interferon response in macrophages expressing SARS-CoV-2 PLpro.
From: Altered ISGylation drives aberrant macrophage-dependent immune responses during SARS-CoV-2 infection
a,b, Schematic of SARS-CoV-2 PLpro (WT (a) and mutant (b)) and their expression in macrophages verified by immunoblotting. c, Bulk ISGylation in type I IFN-treated macrophages expressing either the empty vector, WT PLpro or mutant PLpro in a dose-dependent manner. b,c, Immunoblots are representative of three biologically independent experiments. d,e, Surface staining of MHC-I in macrophages expressing either WT hemagglutinin (HA)-tagged PLpro (d) or the catalytic mutant HA-tagged PLpro (C111A) (e) of SARS-CoV-2. Cells were then treated with dsRNA to induce surface expression of MHC-I. For both samples (WT, mutant C111A) >90% of cells stained positive for HA-tagged PLpro and dsRNA. f,g, Same as d,e in cells expressing USP18 (WT (f) or C64R/C65R mutant (g)). h, Secretion of the indicated cytokines was measured using cytometric beads assay according to the manufacturer’s guidelines and flow cytometry. The error bars represent the mean ± s.d. from four independent experiments. Data are displayed as the mean ± s.d. *P < 0.05 by two-tailed Mann–Whitney U-test versus control (empty vector matched cells). i, Supernatants from the cells described in h were collected and ISG15 was quantified by ISG15 sandwich ELISA. All data are displayed as the mean ± s.d. of four independent experiments. *P < 0.05 by two-tailed Mann–Whitney U-test versus control cells. j, ISG15 levels in the plasma samples collected from the patients with COVID-19 at their first week of disease onset. The error bars represent the mean ± s.d. *P < 0.05 by two-tailed Mann–Whitney U-test versus healthy donors (n = 38 for patients and n = 14 for healthy donors).
