SARS-CoV-2 stimulation induces a TLR7/8-dependent cytokine and chemokine production in PBMC.

Peripheral blood mononuclear cells (PBMC) were left untreated (not stimulated, ns) or Mock-treated as negative controls, or stimulated for 24 hours with the TLR7/8 agonist R848 (5μM) as positive control, with SARS-CoV-2 (CoV2) at different multiplicity of infection (MOI; 0.02, 0.04 and 0.1) in presence or absence of a 30 minute pre-treatment with a specific TLR7/8 inhibitor (I-TLR7/8, 1μM). Production of cytokines (IL-6, TNF-α, IL-1β, IL-10, IL-12p70) (A) and chemokines (CXCL-10, CXCL-9, CCL-2, CXCL-8, CCL-5) (B) was tested by multiparametric cytokine bead arrays in collected cell culture supernatants. Shown results were mean relative values ± SEM of 5 independent experiments. P-values were depicted as follows: *p≤0.05.