Another study on the role of TLR3 in SARS-CoV-2 infection, using SARS-CoV-2 to infect Calu-3/MRC-5 multicellular spheroids (MTCSs), found a prominent increase in TLR3-associated IRF3 expression during the first 24 h after infection, followed by IL-1α, Il-1β, IL-4, IL-6 and IFN-α and IFN-β (Bortolotti et al., 2021). Here, TLR3 is linked to infection.