Figure 6.

Effect of TLR3 antagonist CU-CPT 4a on histamine-induced TLR3 signaling. A, Caco2 cells were infected for 24 h with SARS-CoV-2 in presence of 10 μM CU-CPT 4a. Cells were pretreated with 100 μM histamine and 50 μM famotidine 12 h prior to infection. Lysates were immunoblotted using indicated antibodies. B, CCL2 and ISG15 mRNA levels were measured by RT-PCR using RNA isolated from infected cells treated with histamine, famotidine, and CU-CPT4a similar to panel A. Error bars indicate SD, ∗p < 0.05. C, summary figure showing the effect of famotidine on TLR3-dependent signaling.