Fig 5. Integrin activation, rather than interaction with CD47, modulates SIRPA antiviral activity.

A) Viruses (JUNV-C1, LCMV) and pseudoviruses (VSV-G, SARS-2-S) were incubated with the indicated antibodies for 1 hr on ice before being added to U2OS and 293T-ACE2 cells, respectively. RT-qPCR for viral RNA or luciferase assays were carried out at 24 and 48 hpi, respectively. The data shown represent the average ± SD of 2 (convalescent serum) - 4 independent experiments. One-way ANOVA was used to determine significance. *, P ≤ 0.02; **, P ≤ 0.002. Panel on the right shows western blot analysis of JUNV-C1-infected U2OS cell extracts and virions (5E5 ICs) probed with the same anti-CD47 antibody, anti-Junín virus NP monoclonal antibody or anti-GAPDH. B) U2OS and 293T-mCAT cells were transfected with the indicated siRNAs and 48 hours later were treated with 1mM MnCl₂ for 2 hr. After MnCl₂ treatment, U2OS cells were infected with JUNV-C1, LCMV, VSV, MLV and HSV-1 for 24 hr and 293T-mCAT cells with MLV for 48 hr. Viral RNA and DNA levels were determined by qPCR. The data shown represent the average ± SD of 3–4 independent experiments. Two-way ANOVA was used to determine significance. *, P ≤ 0.05; **, P ≤ 0.005: ***, P ≤ 0.0004; ***, P ≤ 0.0001. C) Primary fibroblasts isolated from WT and SIRPA KO mice were treated with 1mM MnCl₂ for 2 hr and infected with JUNV-C1 for 24 hr. Viral RNA was examined by RT-qPCR. Shown is the average ± SD of 3 independent experiments. Two-way ANOVA used to determine significance. *, P ≤ 0.02; ****, P ≤ 0.0001.