Figure 4.
Full-length SARS-CoV-2 spike stimulates IL-1β secretion from human mast cells via TLR4 signaling. LADR mast cells (2.5 × 105 cells) were pretreated with anti-TLR2 Ab (2 μg/mL), anti-TLR4 Ab (2 μg/mL), or anti-ACE2 Ab (2 μg/mL) for 1 h and then stimulated with recombinant full-length SARS-CoV-2 S (10 ng/mL) for 1 h and 24 h, respectively. Secretion of chymase (A), tryptase (B), and IL-1β (C) was determined by specific ELISAs. All conditions were performed in triplicate for each dataset and repeated 3 times (n = 3). The horizontal brackets indicate the corresponding levels of significance when present (p < 0.05 (*), p < 0.01 (**), p < 0.001 (***), and p < 0.0001 (****)).